Tüm alıştırma soruları

2195 soru

Soru 421Soru

If xx and yy are real numbers, what is the value of x3y3x^3 - y^3?

(1) xy=2x - y = 2
(2) x2+y2=10x^2 + y^2 = 10

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Cevap: BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

Cevap

BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
Combining Statement (1) and Statement (2) allows us to determine the exact value of xy=3xy = 3. Substituting xy=2x - y = 2, x2+y2=10x^2 + y^2 = 10, and xy=3xy = 3 into the factored form x3y3=(xy)(x2+xy+y2)x^3 - y^3 = (x - y)(x^2 + xy + y^2) yields 2×(10+3)=262 \times (10 + 3) = 26. Because this value is uniquely determined, both statements together are sufficient while neither statement alone is sufficient.

Adım Adım Çözüm

1
Rephrase the target expression using algebraic identities.
The target expression x3y3x^3 - y^3 factors into (xy)(x2+xy+y2)(x - y)(x^2 + xy + y^2).
To find x3y3x^3 - y^3, we need the values of (xy)(x - y) and (x2+xy+y2)(x^2 + xy + y^2), or equivalently, (xy)(x - y), (x2+y2)(x^2 + y^2), and xyxy.
2
Evaluate Statement (1) alone.
Statement (1) gives xy=2x - y = 2.
Without knowing x2+y2x^2 + y^2 or xyxy, x3y3x^3 - y^3 can take infinitely many values (for example, if x=2,y=0x=2, y=0, x3y3=8x^3-y^3=8; if x=3,y=1x=3, y=1, x3y3=26x^3-y^3=26). Thus, Statement (1) alone is NOT sufficient.
3
Evaluate Statement (2) alone.
Statement (2) gives x2+y2=10x^2 + y^2 = 10.
Without knowing xyx - y or xyxy, x3y3x^3 - y^3 can take multiple values (for example, if x=10,y=0x=\sqrt{10}, y=0, x3y3=1010x^3-y^3=10\sqrt{10}; if x=3,y=1x=3, y=1, x3y3=26x^3-y^3=26). Thus, Statement (2) alone is NOT sufficient.
4
Combine Statement (1) and Statement (2).
Square Statement (1): (xy)2=22    x22xy+y2=4(x - y)^2 = 2^2 \implies x^2 - 2xy + y^2 = 4. Substitute x2+y2=10x^2 + y^2 = 10: 102xy=4    2xy=6    xy=310 - 2xy = 4 \implies 2xy = 6 \implies xy = 3.
By squaring xyx - y and using x2+y2x^2 + y^2, we isolate a unique value for the product term xyxy.
5
Substitute known values into the target expression.
x3y3=(xy)(x2+y2+xy)=2×(10+3)=26x^3 - y^3 = (x - y)(x^2 + y^2 + xy) = 2 \times (10 + 3) = 26.
Since the expression evaluates to a single, unique numerical value (2626), the two statements together are sufficient.

Anahtar Kavram

Algebraic Expression Rephrasing and Solution Set Invariance in Data Sufficiency
Tahmini Süre:2m 0s
Soru 422Soru

Fill in the blank to logically complete the passage based on the premises provided.

Aşağıdaki boşlukları doldurun

To reduce overall regional water consumption, an agricultural district mandated that farmers replace traditional overhead sprayers with subterranean drip irrigation systems, which deliver water directly to plant roots with minimal evaporative loss. Following the mandate, total volume of water withdrawn for agriculture in the district actually increased, even though no new cropland was developed and climate conditions remained identical. This outcome occurred because the increased water delivery efficiency encouraged farmers to replace drought-tolerant grains with high-value, water-intensive fruit crops. Therefore, the mandate failed to reduce overall water consumption because .
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Cevap

The total increase in water usage resulting from switching to water-intensive fruit crops exceeded the amount of water saved through the implementation of drip irrigation.
The correct logical completion must bridge the premises to explain why total regional water withdrawals rose. Since drip irrigation saves water per unit delivered but prompted a switch to crops that require significantly more water overall, total consumption will only increase if the extra water consumed by the new crops is greater than the water saved by the technology.

Adım Adım Çözüm

1
Identify the paradox presented in the passage.
Drip irrigation increases water application efficiency, yet overall regional agricultural water withdrawals increased.
Understanding the premise conflict is necessary to determine what missing piece of evidence completes the causal explanation.
2
Analyze the explanatory premise provided in the text.
Farmers switched from drought-tolerant grains to high-value, water-intensive fruit crops due to the improved irrigation efficiency.
The change in crop selection introduces a factor that increases total water demand per acre.
3
Synthesize the premises to complete the logical conclusion.
For total water usage to rise despite reduced evaporation loss, the additional water required by the fruit crops must outweigh the physical water savings achieved by drip technology.
A net increase in total volume withdrawn requires that the consumption increase from crop switching is larger than the efficiency savings.

Anahtar Kavram

Completing the passage by synthesizing premises to explain a net quantitative outcome
Soru 423Soru

Premises: A technology firm requires all software engineers who work on cybersecurity infrastructure to complete an advanced cryptography certification. Marcus is a software engineer at the firm who has not completed the advanced cryptography certification.

Based solely on the premises above, evaluate the following statement:
Marcus does not work on cybersecurity infrastructure at the technology firm.

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Cevap: True

Cevap

The statement is True.
The statement is True because it is the contrapositive of the rule stated in the premise. The premise dictates that working on cybersecurity infrastructure requires completing the cryptography certification. Therefore, lacking the certification guarantees that Marcus does not work on cybersecurity infrastructure.

Adım Adım Çözüm

1
Identify the conditional relationship established in the premises.
If an engineer works on cybersecurity infrastructure, then they have completed the cryptography certification (Cybersecurity Infrastructure → Certification).
Establishing the formal conditional rule allows for valid logical deduction.
2
Apply the contrapositive rule of formal logic.
If an engineer has not completed the cryptography certification, then they do not work on cybersecurity infrastructure (NOT Certification → NOT Cybersecurity Infrastructure).
The contrapositive of any valid conditional statement is always logically equivalent and must be true.
3
Compare the contrapositive to the factual premise about Marcus.
Since Marcus has not completed the certification, it logically follows with absolute certainty that Marcus does not work on cybersecurity infrastructure.
Matching the given fact to the valid contrapositive guarantees the conclusion.

Anahtar Kavram

Valid Deduction via Contrapositive
Soru 424Soru

If aa and bb are real numbers, what is the value of a2b2a^2 - b^2?

(1) a+b=7a + b = 7
(2) ab=3a - b = 3

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Cevap: BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

Cevap

Both statements together are sufficient, but neither statement alone is sufficient.
Factoring the target expression yields a2b2=(a+b)(ab)a^2 - b^2 = (a + b)(a - b). Neither statement alone gives both factors, so neither statement alone is sufficient. Combining Statement (1), which gives a+b=7a + b = 7, and Statement (2), which gives ab=3a - b = 3, allows us to calculate a2b2=7×3=21a^2 - b^2 = 7 \times 3 = 21. Therefore, both statements together are sufficient.

Adım Adım Çözüm

1
Rephrase the target question stem algebraically.
Recognize that a2b2=(a+b)(ab)a^2 - b^2 = (a + b)(a - b). The objective is to find the value of the product (a+b)(ab)(a + b)(a - b).
Simplifying the target expression reduces the problem to finding the sum and difference of the variables.
2
Evaluate Statement (1) independently.
Statement (1) states a+b=7a + b = 7. Knowing only a+ba + b leaves aba - b unknown, so a2b2=7(ab)a^2 - b^2 = 7(a - b) can take infinitely many values. Statement (1) is insufficient.
A single linear equation with two variables cannot determine the value of a two-factor product unless the second factor is fixed.
3
Evaluate Statement (2) independently.
Statement (2) states ab=3a - b = 3. Knowing only aba - b leaves a+ba + b unknown, so a2b2=3(a+b)a^2 - b^2 = 3(a + b) can take infinitely many values. Statement (2) is insufficient.
A single difference equation does not uniquely determine the sum of two variables.
4
Evaluate Statements (1) and (2) together.
Combining both statements gives a+b=7a + b = 7 and ab=3a - b = 3. Substituting these values into the rephrased target expression yields a2b2=(7)(3)=21a^2 - b^2 = (7)(3) = 21. A unique numerical value is obtained. Statements combined are sufficient.
Having both component factors allows direct computation of their product without needing to solve for individual values of aa and bb first.

Anahtar Kavram

Algebraic Rephrasing and Difference of Squares in Data Sufficiency
Tahmini Süre:1m 0s
Soru 425Soru

For all non-zero real numbers mm and nn with mnm \neq n, the Data Sufficiency target question "Is m2+n22mn>1\frac{m^2 + n^2}{2mn} > 1?" is algebraically equivalent to the simplified target question "Are mm and nn of opposite signs?".

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Cevap: False

Cevap

False. The target question "Is m2+n22mn>1\frac{m^2 + n^2}{2mn} > 1?" simplifies to "Do mm and nn have the same sign?", not opposite signs.
The statement is false. Rephrasing m2+n22mn>1\frac{m^2 + n^2}{2mn} > 1 yields (mn)22mn>0\frac{(m-n)^2}{2mn} > 0. Because (mn)2>0(m-n)^2 > 0 when mnm \neq n, the ratio is positive if and only if mn>0mn > 0, which requires mm and nn to have the same sign, not opposite signs.

Adım Adım Çözüm

1
Subtract 1 from both sides of the inequality to consolidate into a single rational expression.
m2+n22mn1>0    m22mn+n22mn>0\frac{m^2 + n^2}{2mn} - 1 > 0 \implies \frac{m^2 - 2mn + n^2}{2mn} > 0
Consolidating terms onto one side avoids cross-multiplying by 2mn2mn, which has an unknown sign.
2
Factor the numerator quadratic expression.
(mn)22mn>0\frac{(m - n)^2}{2mn} > 0
Recognize that m22mn+n2m^2 - 2mn + n^2 is a perfect square binomial (mn)2(m - n)^2.
3
Determine the sign conditions of the numerator and denominator.
Since mnm \neq n, (mn)2>0(m - n)^2 > 0 is strictly positive. Therefore, (mn)22mn>0\frac{(m - n)^2}{2mn} > 0 holds if and only if 2mn>0    mn>02mn > 0 \implies mn > 0.
A fraction with a positive numerator is strictly greater than zero if and only if its denominator is also strictly positive.
4
Translate the condition mn>0mn > 0 into verbal sign properties.
mn>0mn > 0 implies that mm and nn share the SAME non-zero sign (both positive or both negative).
Comparing this condition to the statement in the prompt reveals that the claim of 'opposite signs' is incorrect.

Anahtar Kavram

Question Stem Simplification and Target Rephrasing
Soru 426Soru

A regional electric utility company launched a program offering residential customers subsidized smart thermostats designed to lower household electricity usage during peak demand hours. Over the three years following the program's rollout, total peak-period electricity demand on the regional grid increased by 12 percent, even though more than 80 percent of households in the region installed the smart thermostats and each participating household successfully reduced its peak-period power consumption by an average of 15 percent.

Which of the following, if true, most helps to explain the apparent discrepancy described above?

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Cevap: During the three-year period, rapid commercial development led to the construction of several large data centers in the region whose combined peak-period power consumption far exceeded the energy savings achieved by all participating households.

Cevap

During the three-year period, rapid commercial development led to the construction of several large data centers in the region whose combined peak-period power consumption far exceeded the energy savings achieved by all participating households.
The correct answer successfully resolves the paradox by demonstrating that residential consumption is only one component of total grid demand. If large-scale commercial entities like data centers entered the region and consumed power during peak hours in quantities that surpassed the residential savings, overall grid demand would increase despite widespread household efficiency gains.

Adım Adım Çözüm

1
Identify the two conflicting facts presented in the passage.
Fact 1: Over 80% of regional households installed smart thermostats and reduced their individual peak power use by 15%. Fact 2: Total regional grid demand during peak hours increased by 12%.
Resolving a discrepancy requires clearly isolating the two facts that appear contradictory.
2
Determine what information is needed to reconcile both facts.
A valid resolution must explain how total grid demand can rise even when residential demand drops significantly.
The correct answer must account for both facts simultaneously without denying either premise.
3
Evaluate the option introducing commercial data center expansion.
If non-residential peak electricity demand grew substantially due to new high-consumption data centers, total grid demand could increase by 12% despite household savings.
This provides a logical third factor that accounts for the net increase across the entire grid while preserving the fact that households saved energy.

Anahtar Kavram

Resolving Paradoxes: Accounting for Total Volume vs. Subgroup Shifts and Confounding Variables
Soru 427Soru

A municipal energy commission released a report containing the following facts regarding regional energy infrastructure:

• In any municipality where smart meters were installed in more than 80 percent of residential units, peak-hour electricity demand decreased by at least 15 percent during summer months.
• In every municipality where peak-hour electricity demand decreased by at least 15 percent during summer months, municipal electricity tax revenues fell unless local utility rates were increased.
• Last summer, District X had smart meters installed in 90 percent of its residential units, while its local utility rates were held constant.

If the statements above are true, which of the following must also be true regarding District X last summer?

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Cevap: Municipal electricity tax revenues in District X fell.

Cevap

Municipal electricity tax revenues in District X fell last summer.
The conclusion that municipal electricity tax revenues in District X fell is strictly guaranteed by combining the premises. First, because District X installed smart meters in 90% of units (exceeding the 80% threshold), peak-hour electricity demand was guaranteed to decrease by at least 15% last summer. Second, the premises state that whenever such a demand decrease occurs, tax revenues fall unless utility rates are raised. Because District X held utility rates constant, tax revenues must have fallen.

Adım Adım Çözüm

1
Analyze Premise 1 and apply facts given for District X.
Smart meters were installed in 90% of residential units in District X (> 80%). Therefore, peak-hour electricity demand in District X decreased by at least 15% last summer.
The rule states that Smart Meters > 80% guarantees Peak Demand Decrease ≥ 15% in summer.
2
Analyze Premise 2 and synthesize with the result from Step 1.
Since Peak Demand Decrease ≥ 15% occurred, municipal electricity tax revenues fell UNLESS local utility rates were increased.
Conditional rule: Peak Demand Decrease ≥ 15% ⇒ (Tax Revenue Fell OR Utility Rates Increased).
3
Evaluate the condition regarding utility rates in District X.
Local utility rates were held constant (not increased). Therefore, the 'unless' exception is false, forcing the main clause—municipal electricity tax revenues fell—to be true.
When the alternative condition (rate increase) is explicitly negated, the remaining outcome (revenue fall) must occur.

Anahtar Kavram

Identifying Must-Be-True Statements and Valid Deductions
Tahmini Süre:2m 0s
Soru 428Soru

If xx and yy are positive integers, is the product xyxy divisible by 4?

(1) xx is divisible by 4.
(2) x+yx + y is an odd integer.

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Cevap: Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

Cevap

Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
The correct answer is that Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient. Statement (1) establishes that xx is a multiple of 4, so any integer product xyxy must also be a multiple of 4. Statement (2) only guarantees that one of xx or yy is even, which is not enough to determine if the product has two factors of 2.

Adım Adım Çözüm

1
Analyze the question stem target
We need to determine whether xyxy is divisible by 4, given that xx and yy are positive integers.
Establishing integer constraints ensures we evaluate divisibility conditions properly.
2
Evaluate Statement (1) independently
If xx is divisible by 4, then x=4kx = 4k for some positive integer kk. Then xy=(4k)y=4(ky)xy = (4k)y = 4(ky), which is divisible by 4. This gives a definitive YES.
Multiplying any multiple of 4 by an integer results in a multiple of 4. Therefore, Statement (1) alone is sufficient.
3
Evaluate Statement (2) independently
If x+yx + y is odd, one integer is even and the other is odd. Case 1: If x=4x = 4 and y=1y = 1, x+y=5x+y=5 (odd) and xy=4xy = 4 (divisible by 4 -> YES). Case 2: If x=2x = 2 and y=3y = 3, x+y=5x+y=5 (odd) and xy=6xy = 6 (not divisible by 4 -> NO).
Since Statement (2) yields both YES and NO outcomes, it alone is not sufficient.

Anahtar Kavram

Divisibility and Parity Rules in Data Sufficiency
Soru 429Soru

What is the value of the real number kk?

(1) 4k8=124k - 8 = 12
(2) k2=25k^2 = 25

Cevabı ve açıklamayı göster

Cevap: Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

Cevap

Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Solving Statement (1) gives 4k=204k = 20, which simplifies to k=5k = 5. Because this is a single, unique value, Statement (1) alone is sufficient. Statement (2) gives k2=25k^2 = 25, which has two valid solutions (k=5k = 5 or k=5k = -5). Without additional constraints, Statement (2) alone is not sufficient to determine a single value for kk. Therefore, Statement (1) alone is sufficient, but Statement (2) alone is not sufficient.

Adım Adım Çözüm

1
Evaluate Statement (1) independently
4k8=12    4k=20    k=54k - 8 = 12 \implies 4k = 20 \implies k = 5
Solving the linear equation gives a single, unique value for kk. Thus, Statement (1) alone is sufficient.
2
Evaluate Statement (2) independently
k2=25    k=5k^2 = 25 \implies k = 5 or k=5k = -5
Taking the square root yields two distinct possible values for kk. Because kk cannot be uniquely determined, Statement (2) alone is not sufficient.
3
Select the Data Sufficiency decision key
Statement (1) is sufficient, but Statement (2) is not.
This corresponds to the standard option where Statement (1) alone is sufficient.

Anahtar Kavram

Linear vs. Quadratic Degree Sufficiency in Data Sufficiency
Soru 430Soru

In Data Sufficiency analysis, for any non-zero real numbers xx and yy with xy|x| \neq |y|, the target question 'Is x2y2xy>0\frac{x^2 - y^2}{xy} > 0?' is algebraically equivalent to the rephrased target question 'Do xx and yy have opposite signs if and only if x<y|x| < |y|?'

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Cevap: True

Cevap

The statement is TRUE.
The quotient x2y2xy\frac{x^2 - y^2}{xy} is positive in two distinct cases: when x,yx, y have the same sign and x>y|x| > |y| (in which case both 'opposite signs' and 'x<y|x| < |y|' are false, making their biconditional true), or when x,yx, y have opposite signs and x<y|x| < |y| (in which case both components are true, making their biconditional true). In cases where the quotient is negative, the biconditional evaluates to false. Thus, the rephrased target question is logically and algebraically identical to the original target question.

Adım Adım Çözüm

1
Analyze the sign conditions required for the fraction to be positive.
x2y2xy>0\frac{x^2 - y^2}{xy} > 0 requires numerator x2y2x^2 - y^2 and denominator xyxy to have the exact same algebraic sign.
A rational expression AB\frac{A}{B} is strictly positive if and only if A>0,B>0A > 0, B > 0 or A<0,B<0A < 0, B < 0.
2
Evaluate Case 1: Both numerator and denominator are positive (xy>0xy > 0 and x2y2>0x^2 - y^2 > 0).
xy>0    x,yxy > 0 \implies x, y have SAME signs (Opposite signs = False). x2y2>0    x>yx^2 - y^2 > 0 \implies |x| > |y| (x<y|x| < |y| = False).
The rephrased question tests 'Opposite signs     x<y\iff |x| < |y|'. Here, False     \iff False evaluates to TRUE.
3
Evaluate Case 2: Both numerator and denominator are negative (xy<0xy < 0 and x2y2<0x^2 - y^2 < 0).
xy<0    x,yxy < 0 \implies x, y have OPPOSITE signs (Opposite signs = True). x2y2<0    x<yx^2 - y^2 < 0 \implies |x| < |y| (x<y|x| < |y| = True).
The rephrased question tests 'Opposite signs     x<y\iff |x| < |y|'. Here, True     \iff True evaluates to TRUE.
4
Evaluate cases where the fraction is negative to ensure complete equivalence.
If xy>0xy > 0 and x2y2<0x^2 - y^2 < 0, we get False     \iff True (FALSE). If xy<0xy < 0 and x2y2>0x^2 - y^2 > 0, we get True     \iff False (FALSE).
The biconditional statement yields TRUE in exactly the same scenarios where x2y2xy>0\frac{x^2 - y^2}{xy} > 0, establishing strict algebraic equivalence.

Anahtar Kavram

Target Stem Rephrasing via Quotient Sign Decomposition and Logical Biconditional Equivalence
Soru 431Soru

In an effort to lower fleet fuel costs and carbon emissions, a commercial beverage distributor replaced its traditional single-use glass bottles with ultra-lightweight aluminum cans. Although the aluminum cans weighed significantly less per unit than the glass bottles, the company's total annual fleet fuel consumption increased by 14 percent during the year following the transition. This increase occurred despite the company delivering the exact same total volume of beverage product across identical distribution routes, with no changes to vehicle fuel efficiency, delivery schedules, or driver performance. Which of the following, if true, most helps to resolve the apparent discrepancy described above?

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Cevap: Because aluminum cans structural integrity degrades when stacked under heavy weight, delivery trucks could not be loaded as high, requiring 25 percent more truck trips to transport the same volume of product.

Cevap

The apparent discrepancy is resolved by the option explaining that aluminum cans cannot be stacked as high without damage, forcing the company to run 25 percent more truck trips to move the same product volume.
The correct answer identifies a volumetric constraint that counteracts the weight advantage of aluminum cans. If lower structural strength prevents stacking cans to full truck capacity, more delivery trips are required to transport the same total product volume. Running 25 percent more truck trips directly explains why overall fleet fuel consumption increased by 14 percent despite each individual load being lighter.

Adım Adım Çözüm

1
Identify the core facts forming the paradox.
Fact 1: Aluminum cans weigh significantly less per unit than glass bottles. Fact 2: Fleet fuel consumption increased by 14 percent while transporting the exact same product volume over identical routes.
Resolving a discrepancy requires clearly isolating the two seemingly contradictory facts.
2
Evaluate the underlying assumption.
The implicit assumption is that lighter cargo weight directly reduces total transport fuel usage per shipment volume.
Fuel consumption depends not only on weight per unit, but also on the total number of vehicle trips required.
3
Assess how additional constraints impact total vehicle trips.
If structural limitations prevent high vertical stacking, cargo space per truck is underutilized. Consequently, more total truck trips are needed, raising overall fuel usage despite lower total weight per trip.
A valid resolution must account for both facts simultaneously without denying either premise.

Anahtar Kavram

Volume vs. Weight Transport Constraints in Discrepancy Resolution
Tahmini Süre:2m 0s
Soru 432Soru

If mm is a real number, is mm an even integer?

(1) 2m2m is an even integer.
(2) m+1m + 1 is an odd integer.

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Cevap: Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

Cevap

Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
Statement (1) allows mm to be any integer because multiplying any integer by 22 results in an even integer. Therefore, mm could be 33 (odd) or 44 (even), making Statement (1) insufficient. Statement (2) specifies that m+1m + 1 is an odd integer. Subtracting 11 from an odd integer always yields an even integer, so mm must be an even integer. This provides a single, definitive 'Yes' answer, making Statement (2) alone sufficient.

Adım Adım Çözüm

1
Analyze the target question stem.
We need to determine whether mm is an even integer, given that mm is a real number.
Rephrasing the question clarifies that a definitive 'Yes' or definitive 'No' answer is required.
2
Evaluate Statement (1): 2m2m is an even integer.
If m=4m = 4, then 2m=82m = 8 (even integer), and mm is an even integer (Yes). If m=3m = 3, then 2m=62m = 6 (even integer), but mm is an odd integer (No).
Since Statement (1) yields both 'Yes' and 'No' answers, Statement (1) is NOT sufficient.
3
Evaluate Statement (2): m+1m + 1 is an odd integer.
If m+1m + 1 is an odd integer, then m=(m+1)1m = (m + 1) - 1. An odd integer minus 11 is always an even integer.
This guarantees that mm is an even integer, providing a definitive 'Yes'. Thus, Statement (2) ALONE is sufficient.

Anahtar Kavram

Parity and Integer Properties in Data Sufficiency
Soru 433Soru

In a GMAT Data Sufficiency 'Yes/No' question asking whether a real variable x>0x > 0, a statement that establishes definitively that x<0x < 0 is considered INSUFFICIENT because it yields a negative answer to the question stem.

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Cevap: False

Cevap

False. In a GMAT 'Yes/No' Data Sufficiency question, any statement that yields a definitive 'No' answer is sufficient.
The statement is false because GMAT Data Sufficiency decision logic defines sufficiency as achieving an unambiguous binary answer. Obtaining a conclusive 'No' settles the question entirely, rendering the statement sufficient rather than insufficient.

Adım Adım Çözüm

1
Identify the logical structure of the question stem.
The target question is a 'Yes/No' Data Sufficiency question asking whether x>0x > 0.
Understanding whether a question seeks a specific value or a binary condition determines the sufficiency rule.
2
Apply the standard GMAT Data Sufficiency rule for 'Yes/No' questions.
A statement is sufficient if and only if it leads to a consistent 'Yes' in all permissible cases or a consistent 'No' in all permissible cases.
Sufficiency means certainty of outcome, not necessarily an affirmative outcome.
3
Evaluate the outcome of a statement proving x<0x < 0.
Since x<0x < 0 guarantees that xx is never greater than 0, the answer to 'Is x>0x > 0?' is an absolute 'No'.
A guaranteed 'No' provides complete information and solves the question, making the statement sufficient.

Anahtar Kavram

Yes/No Data Sufficiency Decision Rule (Definitive No is Sufficient)
Soru 434Soru

If pp and qq are real numbers such that p0p \neq 0, is p2q<0p^2 q < 0?

(1) q5=q5|q - 5| = q - 5 and q5q \neq 5
(2) p+q=2p + q = 2

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Cevap: Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

Cevap

Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Rephrasing the question stem reveals that because p0p \neq 0, p2p^2 is strictly positive; thus p2q<0p^2 q < 0 is true if and only if q<0q < 0. Statement (1) dictates that q5=q5|q - 5| = q - 5 with q5q \neq 5, which implies q>5q > 5. Because qq is strictly positive, the answer to 'Is q<0q < 0?' is a definitive 'No'. In GMAT Data Sufficiency Yes/No questions, a statement that consistently yields a 'No' answer is sufficient. Statement (2) leaves qq undetermined (qq can be positive or negative depending on pp), so it is insufficient on its own.

Adım Adım Çözüm

1
Rephrase the question stem using algebraic properties.
Since pp is a non-zero real number, p2>0p^2 > 0 for all valid pp. Dividing the inequality p2q<0p^2 q < 0 by p2p^2 yields q<0q < 0. The question simplifies to: 'Is q<0q < 0?'
Simplifying the target expression reduces cognitive complexity before evaluating the statements.
2
Evaluate Statement (1) independently.
The identity k=k|k| = k holds if and only if k0k \ge 0. Thus, q5=q5    q50    q5|q - 5| = q - 5 \implies q - 5 \ge 0 \implies q \ge 5. Combined with q5q \neq 5, we obtain q>5q > 5. If q>5q > 5, then qq is strictly positive, meaning q<0q < 0 is definitively FALSE ('No'). A definitive 'No' answer is sufficient.
In Yes/No Data Sufficiency, any statement that yields a consistent 'Yes' OR a consistent 'No' is sufficient.
3
Evaluate Statement (2) independently.
Given p+q=2p + q = 2, if p=1p = 1, then q=1>0q = 1 > 0 ('No'). If p=5p = 5, then q=3<0q = -3 < 0 ('Yes'). Statement (2) allows both 'Yes' and 'No' outcomes.
Since Statement (2) cannot yield a single definitive Yes/No answer, it is not sufficient.

Anahtar Kavram

Value vs. Yes/No Data Sufficiency Decision Logic
Soru 435Soru

To reduce agricultural nitrate pollution in local river systems, a regional water district plans to install floating artificial wetlands across its primary collection reservoirs. Critics argue that because the wetland plants enter dormancy during the winter—the season when agricultural runoff peaks—the system will fail to reduce nitrate levels when treatment is most needed. Nevertheless, environmental engineers maintain that installing these floating wetlands will substantially reduce the total annual amount of nitrates reaching the rivers. Which of the following, if true, provides the strongest support for the environmental engineers' prediction?

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Cevap: Even when the plants are dormant, dense root matrices beneath the floating mats host cold-tolerant bacterial colonies that decompose nitrates throughout the winter.

Cevap

Even when the plants are dormant, dense root matrices beneath the floating mats host cold-tolerant bacterial colonies that decompose nitrates throughout the winter.
The engineers predict a net annual reduction in nitrate runoff despite critics' objection that plants go dormant in winter during peak runoff. The option stating that cold-tolerant bacterial colonies within root matrices decompose nitrates through the winter directly resolves this concern. By providing a continuous mechanism for nitrate removal when plant uptake is dormant, this choice strongly reinforces the engineers' prediction.

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1
Identify the argument's structure and core conflict.
Premise: Critics point out that wetland plants are dormant in winter when agricultural runoff peaks. Conclusion: Engineers predict that floating wetlands will still significantly lower annual nitrate runoff to rivers.
Strengthening requires finding evidence that fills the logical gap or addresses the vulnerability raised by critics.
2
Determine the necessary strengthening mechanism.
The argument needs evidence showing that nitrate levels will still be reduced in winter despite plant dormancy, or that winter plant dormancy does not impede overall annual removal.
Overcoming the objection about winter inefficiency directly supports the engineers' annual reduction claim.
3
Evaluate the answer choices against the required mechanism.
The fact that cold-tolerant bacteria in the root matrix break down nitrates continuously during winter supplies a missing mechanism that explains how the system works despite plant dormancy.
Supplying an active process for nitrate breakdown during plant dormancy resolves the main vulnerability in the engineers' prediction.

Anahtar Kavram

Strengthening Arguments by Supplying a Missing Mechanism or Countering an Objection
Soru 436Soru

A local coffee shop owner plans to increase total monthly profits by raising the price of all specialty espresso drinks by 10 percent. The owner reasons that because demand for specialty drinks has remained steady over the past year, customers will continue to buy the exact same quantity of drinks despite the price increase.

Which of the following would be most useful to evaluate the validity of the coffee shop owner's argument?

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Cevap: Whether the price increase will cause a significant number of customers to switch to cheaper alternatives or stop buying drinks.

Cevap

Determining whether the price increase will cause a significant number of customers to switch to cheaper alternatives or stop buying drinks is most useful for evaluating the argument.
The correct answer provides information that directly addresses the core assumption of the argument. Applying the Test of Variance: if the price increase causes customers to switch to cheaper drinks or leave, sales volume will decline and ruin profitability; if it does not cause customer loss, revenue and profits will rise as intended. Because the two extreme answers produce opposite impacts on the conclusion, this information is critical for evaluating argument validity.

Adım Adım Çözüm

1
Identify the argument's core structure and conclusion.
Conclusion: Raising specialty espresso prices by 10 percent will increase total monthly profits. Premise: Past demand was steady, so quantity sold will remain unchanged.
Understanding the logic gap between price increase and total revenue requires testing the unstated assumption that volume will not decline.
2
Apply the Test of Variance to evaluate the impact of opposite responses.
If YES (customers switch or stop buying), total volume drops, which shatters the argument. If NO (customers buy the same quantity), total revenue increases, validating the argument.
A question that produces opposite impacts on the argument's conclusion under extreme answers is the definitive evaluation metric.

Anahtar Kavram

Evaluating Argument Validity and Test of Variance
Soru 437Soru

In GMAT Data Sufficiency logic, if a statement determines a single unique numerical value for a variable xx, that statement is sufficient to answer a 'Value' question asking for the exact value of xx, but is insufficient to answer a 'Yes/No' question asking whether x>5x > 5.

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Cevap: False

Cevap

The statement is False. A single unique value for xx provides complete information to answer both a 'Value' question for xx and any 'Yes/No' question regarding xx.
The correct response is False because a statement that yields a single unique numerical value for a variable xx provides complete information about xx. Substituting that single value into the inequality x>5x > 5 results in either a definitive 'Yes' or a definitive 'No'. Because both definitive outcomes satisfy GMAT Data Sufficiency criteria, the statement is sufficient for both question types.

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1
Analyze the condition for sufficiency in a 'Value' Data Sufficiency question.
A 'Value' question requires determining one single, unique value for the variable. Finding a unique value for xx satisfies this requirement.
If more than one value is possible, the statement is insufficient.
2
Analyze the condition for sufficiency in a 'Yes/No' Data Sufficiency question.
A 'Yes/No' question requires a definitive 'Yes' or a definitive 'No'.
Sufficiency means eliminating all ambiguity in the binary decision.
3
Evaluate the effect of knowing a single unique value of xx on the inequality x>5x > 5.
If xx is fixed at a single value (e.g., x=7x = 7), the answer is a definitive 'Yes'. If xx is fixed at another single value (e.g., x=3x = 3), the answer is a definitive 'No'.
In either case, a single value produces a definitive answer with no remaining ambiguity.

Anahtar Kavram

Value vs. Yes/No Data Sufficiency Decision Logic
Soru 438Soru

Hospitals in competitive metropolitan areas frequently suffer substantial revenue loss when surgical procedures are delayed due to sterilizer equipment failure. To eliminate these losses, a regional hospital network plans to replace all of its steam-autoclave sterilizers with modern hydrogen peroxide gas plasma units. Because gas plasma units complete a sterilization cycle in one-third the time required by steam autoclaves, hospital administrators conclude that adopting gas plasma units will virtually eliminate surgical delays caused by equipment unavailability.

Which of the following, if true, most seriously undermines the hospital administrators' conclusion?

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Cevap: Gas plasma units require specialized synthetic containment trays that degrade rapidly under routine use, necessitating mandatory cooling and safety inspection periods that offline the units for longer total duration each week than steam autoclaves.

Cevap

The argument is most weakened by the finding that gas plasma units require frequent inspection and cooling downtime for synthetic trays, resulting in greater overall weekly equipment unavailability than steam autoclaves.
The correct answer identifies an operational constraint—frequent inspection and cooling periods for specialized containment trays—that causes gas plasma units to be offline for longer cumulative periods overall than the older steam autoclaves. Even though each sterilization cycle is individually faster, the increased maintenance downtime reduces total equipment availability, directly contradicting the administrators' conclusion that surgical delays due to unavailable equipment will be eliminated.

Adım Adım Çözüm

1
Deconstruct the core argument
Premise: Gas plasma sterilizers complete individual cycles in one-third the time of steam autoclaves. Conclusion: Replacing steam autoclaves with gas plasma units will eliminate surgical delays caused by equipment unavailability.
Identifying the link between the premise (faster cycle time) and conclusion (reduced overall equipment downtime) exposes the unstated assumption that faster cycle times equal greater total equipment availability.
2
Identify the unstated logical gap
The argument assumes no secondary factors (such as maintenance, inspection, or failure rates) will offset the time saved during individual sterilization cycles.
To weaken a plan-to-goal argument, an option must demonstrate an unintended side effect or constraint that prevents the goal from being achieved.
3
Evaluate the choices against the central gap
The option revealing that maintenance safety inspections offline the gas plasma units for longer total durations per week directly breaks the assumption and proves equipment unavailability will persist or worsen.
This fact directly undermines the conclusion that surgical delays caused by equipment unavailability will be eliminated.

Anahtar Kavram

Weakening Causal and Plan-to-Goal Arguments via Unintended Operational Bottlenecks
Tahmini Süre:2m 0s
Soru 439Soru

A major commercial airline plans to retrofit its long-haul passenger fleet with lightweight carbon-fiber seating frames to reduce overall aircraft weight and lower fuel expenditures over the next five years. Management reasons that because jet fuel represents over thirty percent of total operating expenses, achieving a ten percent reduction in cabin weight will generate substantial net financial savings, even after accounting for the initial capital costs of purchasing and installing the new seats.

Which of the following, if true, most seriously undermines the reasoning behind the airline management's plan?

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Cevap: The carbon-fiber seating frames require specialized bi-annual structural inspections and maintenance that cost significantly more than the monetary value of the projected fuel savings.

Cevap

The argument is most seriously weakened by demonstrating that specialized bi-annual structural inspections and maintenance for the carbon-fiber seats will cost significantly more than the projected fuel savings.
The airline's conclusion rests on the financial calculation that reducing fuel consumption will produce net savings after paying for the initial installation of the seats. Showing that recurring maintenance and inspection costs for these specific seats exceed the monetary value of the fuel saved directly contradicts the assumption of net savings, invalidating management's reasoning.

Adım Adım Çözüm

1
Deconstruct the core argument
Premise: Carbon-fiber seats reduce cabin weight by 10%, lowering fuel usage. Fuel is >30% of operating costs.
Conclusion: The retrofit plan will generate substantial net financial savings over 5 years despite initial installation costs.
Identifying the explicit premises and conclusion reveals the logic gap.
2
Identify the key unstated assumption
The author assumes that there are no additional hidden or ongoing costs associated with carbon-fiber seats that will exceed the projected fuel savings over the 5-year timeframe.
Weakening questions targeting cost-benefit plans frequently rely on unstated operational or maintenance costs.
3
Evaluate the options for logical impact
The statement regarding bi-annual maintenance costs explicitly shows that recurring expenses will exceed the monetary value of fuel saved, rendering net savings impossible.
Directly breaking the financial feasibility premise shatters the conclusion.

Anahtar Kavram

Feasibility and Net Impact in Plan-Based Arguments
Tahmini Süre:2m 0s
Soru 440Soru

In 2024, a major city launched a public transit initiative that made bus travel entirely free for all residents. Transportation officials expected this program to significantly reduce traffic congestion on city roads by encouraging drivers to leave their personal vehicles at home. However, six months after the policy took effect, traffic congestion on major roadways remained virtually unchanged, despite municipal transit data showing a fifty percent increase in total bus ridership.

Which of the following, if true, most helps to explain the apparent discrepancy described above?

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Cevap: The majority of the new bus passengers were individuals who previously walked or rode bicycles to their destinations rather than driving personal vehicles.

Cevap

The apparent paradox is best explained by the fact that the new bus riders were drawn from pedestrians and cyclists rather than former automobile drivers.
The correct answer provides a missing premise that allows both observed facts to be true simultaneously. If the new bus riders previously walked or biked, their shift to bus transit directly accounts for the 50% increase in bus passenger volume while simultaneously explaining why the number of personal vehicles on the road—and thus traffic congestion—did not decline.

Adım Adım Çözüm

1
Identify the two conflicting facts presented in the stimulus.
Fact 1: Bus ridership increased by 50% after buses became free. Fact 2: Traffic congestion on major roadways remained virtually unchanged.
Resolving a discrepancy requires identifying the two statements that seem contradictory on the surface.
2
Determine the missing assumption linking the two facts.
The officials assumed that new bus riders would come from existing car drivers.
If new bus riders did not come from car drivers, then car traffic would not decrease despite the surge in bus passengers.
3
Evaluate the options for a factor that reconciles both facts without contradicting either.
The option stating that new passengers previously walked or cycled accounts for both the 50% increase in bus ridership and the lack of change in car traffic congestion.
Shifting pedestrians and cyclists to buses increases bus ridership while leaving the number of cars on the road identical.

Anahtar Kavram

Resolving Apparent Paradoxes by Identifying Alternative Data Pools
Tahmini Süre:1m 30s
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