Tüm alıştırma soruları

2195 soru

Soru 681Soru

For all real numbers xx and yy, the custom operator Δ\Delta is defined by xΔy=x22yx \Delta y = x^2 - 2y. If kk is a real number such that (3Δk)Δ4=17(3 \Delta k) \Delta 4 = 17, what is the sum of all possible values of kk?

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Cevap: 9

Cevap

The sum of all possible values of kk is 9.
Applying the custom operation rule xΔy=x22yx \Delta y = x^2 - 2y sequentially, the inner evaluation gives 3Δk=92k3 \Delta k = 9 - 2k. Applying the operation again to (92k)Δ4(9 - 2k) \Delta 4 gives (92k)28=17(9 - 2k)^2 - 8 = 17, which simplifies to (92k)2=25(9 - 2k)^2 = 25. Taking the square root gives two valid solutions for 92k9 - 2k: 55 and 5-5. Solving 92k=59 - 2k = 5 yields k=2k = 2, and solving 92k=59 - 2k = -5 yields k=7k = 7. The sum of these two values is 2+7=92 + 7 = 9.

Adım Adım Çözüm

1
Evaluate the inner custom operation 3Δk3 \Delta k.
3Δk=322k=92k3 \Delta k = 3^2 - 2k = 9 - 2k
Apply the definition xΔy=x22yx \Delta y = x^2 - 2y with x=3x = 3 and y=ky = k.
2
Substitute the inner result into the outer expression (92k)Δ4=17(9 - 2k) \Delta 4 = 17.
(92k)22(4)=17    (92k)28=17(9 - 2k)^2 - 2(4) = 17 \implies (9 - 2k)^2 - 8 = 17
Apply the definition xΔy=x22yx \Delta y = x^2 - 2y with x=92kx = 9 - 2k and y=4y = 4.
3
Isolate the squared term and solve for 92k9 - 2k.
(92k)2=25    92k=5(9 - 2k)^2 = 25 \implies 9 - 2k = 5 or 92k=59 - 2k = -5
Adding 8 to both sides gives 25; taking the square root requires considering both positive and negative roots.
4
Solve each linear equation for kk and calculate their sum.
Case 1: 92k=5    2k=4    k=29 - 2k = 5 \implies 2k = 4 \implies k = 2.
Case 2: 92k=5    2k=14    k=79 - 2k = -5 \implies 2k = 14 \implies k = 7.
Sum = 2+7=92 + 7 = 9.
Solving both equations yields all possible values for kk.

Anahtar Kavram

Custom Operator Evaluation and Quadratic Equation Root Extraction
Tahmini Süre:2m 0s
Soru 682Soru

Printer Alpha can fabricate a set of architectural prototypes in 44 hours operating alone at a constant rate. Printer Beta can fabricate the exact same set of prototypes in 1212 hours operating alone at a constant rate. If both printers operate simultaneously at their respective constant rates, how many hours will it take them to fabricate one set of architectural prototypes?

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Cevap: 33 hours

Cevap

33 hours
The correct answer is 33 hours. The rate of Printer Alpha is 14\frac{1}{4} of the prototype set per hour, and the rate of Printer Beta is 112\frac{1}{12} of the set per hour. Their combined rate when operating simultaneously is 14+112=412=13\frac{1}{4} + \frac{1}{12} = \frac{4}{12} = \frac{1}{3} set per hour. Therefore, the time required to complete 11 set working together is 113=3\frac{1}{\frac{1}{3}} = 3 hours.

Adım Adım Çözüm

1
Determine the individual work rate for Printer Alpha.
Printer Alpha completes 14\frac{1}{4} of the job per hour.
Work rate is defined as job completed divided by time taken.
2
Determine the individual work rate for Printer Beta.
Printer Beta completes 112\frac{1}{12} of the job per hour.
Work rate is defined as job completed divided by time taken.
3
Add the individual rates to find the combined work rate.
Combined rate = 14+112=312+112=412=13\frac{1}{4} + \frac{1}{12} = \frac{3}{12} + \frac{1}{12} = \frac{4}{12} = \frac{1}{3} of the job per hour.
When entities work together, their individual rates add up.
4
Calculate the total time required for the combined rate to complete 1 job.
Time = 1Combined Rate=113=3\frac{1}{\text{Combined Rate}} = \frac{1}{\frac{1}{3}} = 3 hours.
Time is the reciprocal of the combined rate.

Anahtar Kavram

Combined Work Rate
Tahmini Süre:45s
Soru 683Soru

For all real numbers pp and qq, the operation \nabla is defined by pq=2p+3qpqp \nabla q = 2p + 3q - pq. What is the value of 343 \nabla 4?

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Cevap: 6

Cevap

The value of 343 \nabla 4 is 6.
Substituting p=3p = 3 and q=4q = 4 directly into the expression 2p+3qpq2p + 3q - pq gives 2(3)+3(4)(3)(4)=6+1212=62(3) + 3(4) - (3)(4) = 6 + 12 - 12 = 6.

Adım Adım Çözüm

1
Identify the assigned values for the operator inputs.
p=3p = 3 and q=4q = 4.
The expression 343 \nabla 4 matches pqp \nabla q with pp as the first argument and qq as the second.
2
Substitute p=3p = 3 and q=4q = 4 into the custom operation formula 2p+3qpq2p + 3q - pq.
2(3)+3(4)(3)(4)2(3) + 3(4) - (3)(4)
Direct evaluation of the defined function rule.
3
Perform the multiplication and algebraic addition/subtraction.
6+1212=66 + 12 - 12 = 6
Simplifying numerical operations gives the final result.

Anahtar Kavram

Custom Operator Evaluation
Soru 684Soru

In a technology firm of 100100 software engineers, 6565 engineers know Python and 4545 know Java. If 2020 engineers know both Python and Java, how many of the engineers know neither Python nor Java?

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Cevap: 1010

Cevap

The number of engineers who know neither Python nor Java is 1010.
The total number of engineers is 100100. By inclusion-exclusion, the union of Python and Java speakers is 65+4520=9065 + 45 - 20 = 90. The number of engineers who know neither language is the total minus the union, 10090=10100 - 90 = 10.

Adım Adım Çözüm

1
Calculate the number of engineers who know at least one language using the Inclusion-Exclusion Principle.
At least one=Python+JavaBoth=65+4520=90\text{At least one} = \text{Python} + \text{Java} - \text{Both} = 65 + 45 - 20 = 90
Engineers who know both languages are counted in both individual totals, so their count must be subtracted once to avoid double counting.
2
Subtract the number of engineers who know at least one language from the total number of engineers to find those who know neither.
Neither=TotalAt least one=10090=10\text{Neither} = \text{Total} - \text{At least one} = 100 - 90 = 10
The total group consists of those who know at least one language plus those who know neither.

Anahtar Kavram

Two-Set Inclusion-Exclusion Principle
Tahmini Süre:45s
Soru 685Soru

Let SS be the set of all real solutions to the polynomial equation (x25x+6)(x27x+12)=(x3)2(x2)(x^2 - 5x + 6)(x^2 - 7x + 12) = (x - 3)^2(x - 2). What is the sum of all elements in set SS?

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Cevap: 10

Cevap

The sum of all distinct real elements in set SS is 10.
The correct answer is obtained by completely factoring both quadratic expressions on the left side into (x2)(x3)2(x4)(x - 2)(x - 3)^2(x - 4). Moving all terms to one side gives (x2)(x3)2(x4)(x3)2(x2)=0(x - 2)(x - 3)^2(x - 4) - (x - 3)^2(x - 2) = 0. Factoring out (x2)(x3)2(x - 2)(x - 3)^2 yields (x2)(x3)2(x5)=0(x - 2)(x - 3)^2(x - 5) = 0. The distinct solutions are 2, 3, and 5. Their sum is 10.

Adım Adım Çözüm

1
Factor the quadratic expressions on the left side of the equation.
x25x+6=(x2)(x3)x^2 - 5x + 6 = (x - 2)(x - 3) and x27x+12=(x3)(x4)x^2 - 7x + 12 = (x - 3)(x - 4). Substituting these into the left side yields (x2)(x3)2(x4)(x - 2)(x - 3)^2(x - 4).
Factoring simplifies higher-degree polynomial expressions into linear factors.
2
Set up the equation with all terms on one side to avoid dividing by variable expressions.
(x2)(x3)2(x4)(x3)2(x2)=0(x - 2)(x - 3)^2(x - 4) - (x - 3)^2(x - 2) = 0.
Dividing by variable expressions can cause the loss of valid roots.
3
Factor out the common polynomial factor (x2)(x3)2(x - 2)(x - 3)^2.
(x2)(x3)2[(x4)1]=0(x - 2)(x - 3)^2 [(x - 4) - 1] = 0, which simplifies to (x2)(x3)2(x5)=0(x - 2)(x - 3)^2(x - 5) = 0.
Factoring allows finding all roots by setting each factor equal to zero.
4
Identify the distinct real solutions forming set SS and compute their sum.
The roots are x=2x = 2, x=3x = 3, and x=5x = 5. Thus, S={2,3,5}S = \{2, 3, 5\}. The sum of elements in SS is 2+3+5=102 + 3 + 5 = 10.
A set contains only unique elements, so repeated roots are counted only once.

Anahtar Kavram

Factoring polynomial equations completely without dividing by variable expressions
Tahmini Süre:2m 0s
Soru 686Soru

Data Pipeline A can process a standard batch of records in 1212 hours, while Data Pipeline B can process the same batch of records in 1818 hours. Data Pipeline A begins processing a batch alone and operates for 44 hours before Data Pipeline B is brought online to assist. Both pipelines then continue processing together at their respective constant rates until the batch is completely processed. What is the total time, in hours, required to process the entire batch of records from start to finish?

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Cevap: 8.88.8

Cevap

8.88.8 hours (or 8458\frac{4}{5} hours)
The rate of Pipeline A is 112\frac{1}{12} per hour, so in 44 hours it completes 4×112=134 \times \frac{1}{12} = \frac{1}{3} of the job. The remaining 23\frac{2}{3} of the job is completed by both pipelines working together. Their combined rate is 112+118=536\frac{1}{12} + \frac{1}{18} = \frac{5}{36} per hour. The time required for the joint phase is 2/35/36=4.8\frac{2/3}{5/36} = 4.8 hours. Adding the initial 44 hours gives a total time of 8.88.8 hours.

Adım Adım Çözüm

1
Calculate the work completed by Data Pipeline A alone during the first 44 hours.
Pipeline A's rate is 112\frac{1}{12} batch/hour. Work done in 44 hours = 4×112=134 \times \frac{1}{12} = \frac{1}{3} of the batch.
Determining the completed portion establishes how much work remains for the combined phase.
2
Determine the remaining fraction of work to be done.
Remaining work = 113=231 - \frac{1}{3} = \frac{2}{3} of the batch.
The combined pipelines only need to finish the remaining portion of the job.
3
Calculate the combined processing rate of both pipelines.
Combined rate = 112+118=336+236=536\frac{1}{12} + \frac{1}{18} = \frac{3}{36} + \frac{2}{36} = \frac{5}{36} batch/hour.
Rates add when entities work simultaneously on the same task.
4
Calculate the time required for both pipelines to finish the remaining work together.
Joint time = Remaining WorkCombined Rate=2/35/36=23×365=245=4.8\frac{\text{Remaining Work}}{\text{Combined Rate}} = \frac{2/3}{5/36} = \frac{2}{3} \times \frac{36}{5} = \frac{24}{5} = 4.8 hours.
Dividing remaining work by the combined rate gives the duration of the second phase.
5
Calculate total time from start to finish.
Total time = 4 hours (phase 1)+4.8 hours (phase 2)=8.84 \text{ hours (phase 1)} + 4.8 \text{ hours (phase 2)} = 8.8 hours.
Summing both phase durations gives the total time required for the entire process.

Anahtar Kavram

Work Rate and Combined Work
Tahmini Süre:2m 0s
Soru 687Soru

At a software company, the ratio of senior developers to junior developers was initially 3:73 : 7. During a quarterly hiring push, 1212 senior developers and 1818 junior developers were hired, but 66 junior developers resigned shortly thereafter. As a result, the ratio of senior developers to junior developers became 4:94 : 9. If a certain number NN of senior developers were subsequently promoted out of the developer pool such that the ratio of senior developers to junior developers became 5:125 : 12, what is the value of NN?

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Cevap: 12

Cevap

The value of NN is 1212.
By defining the initial counts as 3x3x and 7x7x, accounting for the net additions (+12+12 seniors and +12+12 juniors), and solving 3x+127x+12=49\frac{3x+12}{7x+12} = \frac{4}{9}, we find x=60x = 60. Thus, there are 192192 senior developers and 432432 junior developers after hiring. Setting the final ratio 192N432=512\frac{192-N}{432} = \frac{5}{12} gives 192N=180192 - N = 180, which yields N=12N = 12.

Adım Adım Çözüm

1
Define initial quantities using a common multiplier xx.
Initial senior developers = 3x3x, Initial junior developers = 7x7x.
The given initial ratio of senior to junior developers is 3:73 : 7.
2
Account for changes in staffing and set up the equation for the new ratio.
Senior developers after hiring = 3x+123x + 12; Net junior developer change = +186=+12+18 - 6 = +12, so Junior developers after hiring = 7x+127x + 12. Equation: 3x+127x+12=49\frac{3x + 12}{7x + 12} = \frac{4}{9}.
12 seniors were added, while 18 juniors were hired and 6 resigned.
3
Solve for the multiplier xx.
9(3x+12)=4(7x+12)    27x+108=28x+48    x=609(3x + 12) = 4(7x + 12) \implies 27x + 108 = 28x + 48 \implies x = 60.
Cross-multiplication yields the value of the algebraic multiplier xx.
4
Calculate post-hiring developer counts.
Senior developers post-hiring = 3(60)+12=1923(60) + 12 = 192; Junior developers post-hiring = 7(60)+12=4327(60) + 12 = 432.
Substitute x=60x = 60 back into the expressions for post-hiring developer counts.
5
Determine NN using the final ratio 5:125 : 12.
192N432=512    192N=5×36=180    N=192180=12\frac{192 - N}{432} = \frac{5}{12} \implies 192 - N = 5 \times 36 = 180 \implies N = 192 - 180 = 12.
Junior developer count remains unchanged (432432) while senior developer count decreases by NN.

Anahtar Kavram

Multi-step algebraic ratio setup and alteration of part-to-part proportions
Soru 688Soru

What is the sum of all real solutions to the equation x(x3)=10x(x - 3) = 10?

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Cevap: 3

Cevap

The sum of all real solutions to the equation is 3.
Expanding the equation x(x3)=10x(x - 3) = 10 yields x23x10=0x^2 - 3x - 10 = 0. Factoring this expression gives (x5)(x+2)=0(x - 5)(x + 2) = 0, yielding solutions x=5x = 5 and x=2x = -2. The sum of these two real solutions is 5+(2)=35 + (-2) = 3. Alternatively, applying Vieta's formula directly to x23x10=0x^2 - 3x - 10 = 0 gives the sum of roots as ba=31=3-\frac{b}{a} = -\frac{-3}{1} = 3.

Adım Adım Çözüm

1
Expand the left side of the equation.
x23x=10x^2 - 3x = 10
Multiply xx across the binomial (x3)(x - 3) to convert to standard polynomial form.
2
Rearrange the equation into standard quadratic form ax2+bx+c=0ax^2 + bx + c = 0.
x23x10=0x^2 - 3x - 10 = 0
Subtract 10 from both sides so the equation equals zero.
3
Factor the quadratic expression.
(x5)(x+2)=0(x - 5)(x + 2) = 0
Find two numbers that multiply to 10-10 and add up to 3-3, which are 5-5 and 22.
4
Solve for the roots of the equation.
x=5x = 5 or x=2x = -2
Apply the zero-product property: set each factor equal to zero.
5
Calculate the sum of the solutions.
Sum =5+(2)=3= 5 + (-2) = 3
Add the two real solutions together. Alternatively, by Vieta's formulas, the sum of roots is ba=31=3-\frac{b}{a} = -\frac{-3}{1} = 3.

Anahtar Kavram

Quadratic Equations and Polynomial Factoring
Tahmini Süre:1m 0s
Soru 689Soru

Scanner X can scan a batch of archival documents in 66 hours operating alone at a constant rate. Scanner Y can scan the exact same batch of documents in 33 hours operating alone at a constant rate. Working together simultaneously at their respective constant rates, how many hours will it take Scanner X and Scanner Y to scan the entire batch of documents?

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Cevap: 2

Cevap

It will take Scanner X and Scanner Y a total of 22 hours to scan the batch of documents together.
To calculate combined completion time, add the rates of each machine rather than their completion times. Scanner X completes 16\frac{1}{6} of the task per hour, and Scanner Y completes 13\frac{1}{3} (or 26\frac{2}{6}) of the task per hour. Together, they complete 16+26=36=12\frac{1}{6} + \frac{2}{6} = \frac{3}{6} = \frac{1}{2} of the task per hour. The inverse of this rate gives the total time required: 22 hours.

Adım Adım Çözüm

1
Calculate individual work rates per hour.
Scanner X rate = 16\frac{1}{6} batch/hour, Scanner Y rate = 13\frac{1}{3} batch/hour.
Work rate is defined as Rate=WorkTime\text{Rate} = \frac{\text{Work}}{\text{Time}}.
2
Add the individual rates together to find the total combined rate.
Combined rate = 16+13=36=12\frac{1}{6} + \frac{1}{3} = \frac{3}{6} = \frac{1}{2} batch/hour.
When entities work together simultaneously, their work rates are additive.
3
Compute total time taken for 1 whole batch.
Total Time = 22 hours.
Time is the reciprocal of the combined work rate: Time=1Combined Rate\text{Time} = \frac{1}{\text{Combined Rate}}.

Anahtar Kavram

Combined Work Rate
Tahmini Süre:45s
Soru 690Soru

Three automated data-processing pipelines, AA, BB, and CC, process incoming dataset files at constant individual rates. Pipeline AA operating alone can complete a standard processing job in 1010 hours, while Pipeline BB operating alone can complete the same job in 1515 hours.

The processing begins with Pipelines AA and BB working together at their standard rates for 22 hours. At that point, Pipeline AA encounters a network slowdown that reduces its processing rate by 50%50\% for the remainder of the job. Pipelines AA and BB continue working at these modified rates for another 22 hours, after which Pipeline CC is brought online to assist them. If Pipeline CC operating alone at its constant rate could finish the entire job in 1010 hours, how many total hours from the start of the processing will it take for the job to be completed?

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Cevap: 6

Cevap

The total time required to complete the job is 6 hours.
To solve multi-stage work rate problems, determine the rate per unit of time for each participant, multiply by the duration of each operational phase, and track the remaining fraction of the job. In the first 2 hours, Pipelines AA and BB complete 13\frac{1}{3} of the job. In the next 2 hours with Pipeline AA at half speed (rate 120\frac{1}{20}), they complete an additional 730\frac{7}{30} of the job, leaving 1330\frac{13}{30} unfinished. When Pipeline CC (rate 110\frac{1}{10}) joins, the combined rate becomes 1360\frac{13}{60} per hour, taking exactly 2 more hours to complete the remaining 1330\frac{13}{30} of the job. Adding all three intervals (2+2+22 + 2 + 2) yields a total time of 6 hours.

Adım Adım Çözüm

1
Determine the individual hourly work rates for each pipeline
Rate of Pipeline A=110A = \frac{1}{10} job/hr, Rate of Pipeline B=115B = \frac{1}{15} job/hr, Rate of Pipeline C=110C = \frac{1}{10} job/hr.
Work rate is the reciprocal of the total time taken to complete one full job.
2
Calculate work completed during Stage 1 (first 2 hours)
Combined rate = 110+115=16\frac{1}{10} + \frac{1}{15} = \frac{1}{6} job/hr. Work done = 2×16=132 \times \frac{1}{6} = \frac{1}{3} of the job.
Both Pipeline AA and Pipeline BB operate together at their standard rates for 2 hours.
3
Calculate work completed during Stage 2 (next 2 hours)
Modified rate of Pipeline A=0.50×110=120A = 0.50 \times \frac{1}{10} = \frac{1}{20} job/hr. Combined rate = 120+115=760\frac{1}{20} + \frac{1}{15} = \frac{7}{60} job/hr. Work done = 2×760=7302 \times \frac{7}{60} = \frac{7}{30} of the job.
Pipeline AA's efficiency drops by 50%, while Pipeline BB remains unchanged.
4
Calculate the remaining work after 4 hours
Total work completed = 13+730=1730\frac{1}{3} + \frac{7}{30} = \frac{17}{30}. Remaining work = 11730=13301 - \frac{17}{30} = \frac{13}{30}.
Subtracting cumulative work done from the total job (1) leaves the remaining portion.
5
Calculate the duration of Stage 3 when Pipeline CC joins
Combined rate = 120+115+110=1360\frac{1}{20} + \frac{1}{15} + \frac{1}{10} = \frac{13}{60} job/hr. Time required = 13/3013/60=2\frac{13/30}{13/60} = 2 hours.
Dividing remaining work by the combined rate of all three active pipelines gives the remaining time.
6
Sum the durations of all stages to find total elapsed time
Total time = 2 hours+2 hours+2 hours=6 hours2\text{ hours} + 2\text{ hours} + 2\text{ hours} = 6\text{ hours}.
The question asks for total elapsed time from the start of processing.

Anahtar Kavram

Multi-stage combined work rate problems require tracking accumulated work completed across distinct intervals with changing worker rates.
Soru 691Soru

Pumps X, Y, and Z, operating simultaneously at their respective constant rates, can fill an empty reservoir in 44 hours. Operating alone at its constant rate, Pump X can fill 15\frac{1}{5} of the reservoir in 22 hours. The rate at which Pump Y fills the reservoir is 50%50\% greater than the rate at which Pump Z fills the reservoir. If Pump X and Pump Z work together for 33 hours, and then Pump Y is turned on so that all three pumps work together until the reservoir is full, how many additional hours will it take to finish filling the remainder of the reservoir?

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Cevap: 22252 \frac{2}{25} hours

Cevap

22252 \frac{2}{25} hours
The rate of Pump X is 110\frac{1}{10} reservoir/hour, and the combined rate of all three pumps is 14\frac{1}{4} reservoir/hour. Thus, the combined rate of Pumps Y and Z is 14110=320\frac{1}{4} - \frac{1}{10} = \frac{3}{20} reservoir/hour. Given ry=1.5rzr_y = 1.5 r_z, setting 52rz=320\frac{5}{2} r_z = \frac{3}{20} yields rz=350r_z = \frac{3}{50} and ry=9100r_y = \frac{9}{100}. The combined rate of Pumps X and Z is 110+350=425\frac{1}{10} + \frac{3}{50} = \frac{4}{25}. In 33 hours, Pumps X and Z complete 3×425=12253 \times \frac{4}{25} = \frac{12}{25} of the reservoir, leaving 1325\frac{13}{25} un-filled. When all three pumps operate, their combined rate is 14\frac{1}{4}. The additional time required is 13/251/4=5225=2225\frac{13/25}{1/4} = \frac{52}{25} = 2 \frac{2}{25} hours.

Adım Adım Çözüm

1
Determine the individual rate of Pump X and the total combined rate of all three pumps.
Pump X's rate rx=1/52=110r_x = \frac{1/5}{2} = \frac{1}{10} of the reservoir per hour. The total combined rate of Pumps X, Y, and Z is rx+ry+rz=14r_x + r_y + r_z = \frac{1}{4} of the reservoir per hour.
Work rate is equal to work completed divided by time elapsed.
2
Determine the individual work rates of Pump Y and Pump Z.
The combined rate of Y and Z is ry+rz=14110=320r_y + r_z = \frac{1}{4} - \frac{1}{10} = \frac{3}{20}. Since ry=1.5rz=32rzr_y = 1.5 r_z = \frac{3}{2} r_z, we have 52rz=320\frac{5}{2} r_z = \frac{3}{20}, which gives rz=350r_z = \frac{3}{50} and ry=9100r_y = \frac{9}{100}.
Use the given relationship between the rates of Pump Y and Pump Z to solve for their individual values.
3
Calculate the work completed during the first 3 hours by Pumps X and Z working together, and find the remaining work.
The combined rate of X and Z is rx+rz=110+350=850=425r_x + r_z = \frac{1}{10} + \frac{3}{50} = \frac{8}{50} = \frac{4}{25}. In 3 hours, they complete 3×425=12253 \times \frac{4}{25} = \frac{12}{25} of the reservoir. The remaining work is 11225=13251 - \frac{12}{25} = \frac{13}{25}.
Work done equals combined rate multiplied by time worked.
4
Calculate the additional time required for all three pumps working together to finish the remaining work.
Time t=Remaining WorkCombined Rate of X, Y, Z=13/251/4=5225=2225t = \frac{\text{Remaining Work}}{\text{Combined Rate of X, Y, Z}} = \frac{13/25}{1/4} = \frac{52}{25} = 2 \frac{2}{25} hours.
Time needed is remaining work divided by the total combined rate of all active pumps.

Anahtar Kavram

Work Rate and Combined Work
Tahmini Süre:2m 30s
Soru 692Soru

A beverage recipe requires mixing orange juice and cranberry juice in a ratio of 4:14 : 1. If a caterer uses 1212 liters of orange juice, how many liters of cranberry juice must be added to maintain this ratio?

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Cevap: 3

Cevap

The caterer must add 3 liters of cranberry juice.
The ratio of orange juice to cranberry juice is 4:14:1. Since 1212 liters of orange juice represents 44 parts, each part equals 124=3\frac{12}{4} = 3 liters. Therefore, 11 part of cranberry juice equals 33 liters.

Adım Adım Çözüm

1
Set up the ratio equation based on the recipe requirements.
Orange Juice : Cranberry Juice = 4:14 : 1
The problem states that for every 4 parts of orange juice, 1 part of cranberry juice is required.
2
Calculate the unknown amount of cranberry juice using the given quantity of orange juice.
Cranberry Juice = 124=3\frac{12}{4} = 3 liters
Since 12 liters represents 4 equal parts, dividing 12 by 4 yields the size of 1 part.

Anahtar Kavram

Direct Ratio and Proportion Scaling
Soru 693Soru

A corporate marketing team initially allocates its quarterly budget among Digital, Print, and Event advertising in the ratio 5:3:25 : 3 : 2, respectively. Midway through the quarter, $12,000\$12,000 is reallocated from Digital advertising to Event advertising, while the Print advertising budget remains unchanged. As a result of this transfer, the ratio of the Digital advertising budget to the Event advertising budget becomes 4:34 : 3. What was the total initial quarterly budget, in dollars, allocated across all three advertising categories?

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Cevap: 120000

Cevap

The total initial quarterly budget allocated across all three categories was 120,000 dollars.
By representing the initial amounts as 5x5x, 3x3x, and 2x2x, the total initial budget is 10x10x. Accounting for the $12,000\$12,000 shift gives 5x12,0002x+12,000=43\frac{5x - 12,000}{2x + 12,000} = \frac{4}{3}. Solving yields x=12,000x = 12,000, which gives a total initial budget of 10×12,000=120,00010 \times 12,000 = 120,000 dollars.

Adım Adım Çözüm

1
Define initial allocations using a multiplier variable
Digital = 5x5x, Print = 3x3x, Event = 2x2x, Total Initial Budget = 10x10x
Representing ratio components algebraically allows set up of linear equations.
2
Adjust allocations according to the budget transfer
New Digital = 5x12,0005x - 12,000, New Event = 2x+12,0002x + 12,000
Reallocating $12,000\$12,000 reduces Digital by 12,000 and increases Event by 12,000.
3
Set up and solve the ratio equation for xx
5x12,0002x+12,000=4315x36,000=8x+48,0007x=84,000x=12,000\frac{5x - 12,000}{2x + 12,000} = \frac{4}{3} \Rightarrow 15x - 36,000 = 8x + 48,000 \Rightarrow 7x = 84,000 \Rightarrow x = 12,000
Equating the altered ratio of Digital to Event to 4/34/3 allows solving for multiplier xx.
4
Compute the total initial budget
Total = 10×12,000=120,00010 \times 12,000 = 120,000
Substituting x=12,000x = 12,000 back into the total initial expression 10x10x gives the final answer.

Anahtar Kavram

Altering non-isolated ratios through part-to-part modifications
Soru 694Soru

For all real numbers xx and yy, the custom operation \diamondsuit is defined by xy=3x2y+1x \diamondsuit y = 3x - 2y + 1. What is the value of 545 \diamondsuit 4?

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Cevap: 8

Cevap

The value of 545 \diamondsuit 4 is 8.
Substituting x=5x = 5 and y=4y = 4 into the operation xy=3x2y+1x \diamondsuit y = 3x - 2y + 1 yields 3(5)2(4)+1=158+1=83(5) - 2(4) + 1 = 15 - 8 + 1 = 8.

Adım Adım Çözüm

1
Substitute the operands into the custom operator rule
5 \diamondsuit 4 = 3(5) - 2(4) + 1
The first term 55 corresponds to xx and the second term 44 corresponds to yy in the formula.
2
Simplify the numeric expression
15 - 8 + 1 = 8
Multiply first, then perform subtraction and addition from left to right.

Anahtar Kavram

Function Definitions, Evaluation, and Custom Operators
Soru 695Soru

To reduce mortality rates from aggressive skin cancers, a network of dermatology clinics plans to deploy a new automated scanning device that detects subtle tissue irregularities undetectable by visual examination alone. Clinic administrators claim that because the device identified early-stage tissue irregularities in 30 percent more patients during trials than visual exams did, deploying this technology across all clinics will significantly decrease overall skin cancer mortality among their patients. Which of the following, if true, most seriously undermines the clinic administrators' argument?

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Cevap: The vast majority of the additional tissue irregularities detected by the automated scanning device are harmless, benign growths that never progress to malignant cancer.

Cevap

The argument is most seriously weakened by the fact that the vast majority of the additional tissue irregularities detected by the scanning device are benign growths that never develop into malignant cancer.
The correct answer demonstrates that the 30 percent increase in detected tissue irregularities consists almost entirely of harmless, benign growths. Because these growths would never have developed into fatal skin cancer anyway, detecting them provides no mortality reduction benefit, thereby undermining the administrators' central conclusion.

Adım Adım Çözüm

1
Identify the conclusion and premises of the argument.
Premise: The new scanning device detected 30% more early-stage tissue irregularities than visual exams. Conclusion: Deploying the device across all clinics will significantly reduce skin cancer mortality.
Understanding the structure reveals the core assumption: that detecting these additional tissue irregularities leads to early treatment of fatal cancers.
2
Evaluate the underlying assumption connecting premise to conclusion.
The author assumes that the extra anomalies detected represent dangerous, early-stage cancers that would otherwise become fatal.
To weaken the argument, we must find evidence that undermines this key assumption.
3
Select the option that shows the extra detections do not prevent fatal cancer.
If the additional detected irregularities are benign growths that never turn into cancer, identifying them does not reduce cancer mortality.
This directly undermines the claim that higher detection rates of these irregularities will decrease patient deaths.

Anahtar Kavram

Weakening Arguments by Severing the Premise-Conclusion Assumption
Soru 696Soru

An executive board must arrange 7 books side-by-side on a display shelf: 3 identical copies of a Finance textbook, 2 identical copies of an Economics textbook, and 2 distinct novels (Novel A and Novel B). How many distinct linear arrangements of these 7 books are possible such that Novel A and Novel B are not placed adjacent to each other?

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Cevap: 300

Cevap

300
To find the number of distinct arrangements where Novel A and Novel B are not adjacent, use complementary counting. First, compute the total distinct arrangements of the 7 books with identical items: 7! / (3! * 2!) = 420. Next, find the number of arrangements where Novel A and Novel B ARE adjacent by bundling them as one unit [AB], which has 2 internal orderings (AB or BA). Arranging the 6 units ([AB], 3 Finance, 2 Economics) gives 6! / (3! * 2!) = 60 ways. Multiplying by 2 internal orderings gives 120 adjacent arrangements. Subtracting these from the total yields 420 - 120 = 300.

Adım Adım Çözüm

1
Calculate the unrestricted total number of distinct permutations of the 7 books.
420 distinct arrangements
There are 7 total items with 3 identical Finance books and 2 identical Economics books. Using the formula N! / (n1! * n2! ...), we get 7! / (3! * 2!) = 5,040 / 12 = 420.
2
Calculate the number of forbidden arrangements where Novel A and Novel B are adjacent.
120 forbidden arrangements
Treat Novel A and Novel B as a single composite item [AB]. There are 2! = 2 ways to order A and B inside this block (AB or BA). Then, arrange the 6 items ([AB] and the 5 textbooks with repetitions): 6! / (3! * 2!) = 60. Multiplying by 2 internal orderings gives 2 * 60 = 120.
3
Subtract the forbidden (adjacent) arrangements from the total unrestricted arrangements.
300 valid arrangements
By complementary counting, Valid = Total - Forbidden = 420 - 120 = 300.

Anahtar Kavram

Counting permutations with indistinguishable items and non-adjacency restrictions using complementary counting
Tahmini Süre:2m 0s
Soru 697Soru

For all non-zero real numbers xx, the function ff is defined by f(x)=x242xf(x) = \frac{x^2 - 4}{2x}, and the function gg is defined by g(x)=3x1g(x) = 3x - 1. What is the positive value of aa for which f(g(a))=0f(g(a)) = 0?

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Cevap: 1

Cevap

The positive value of aa for which f(g(a))=0f(g(a)) = 0 is 1.
To solve f(g(a))=0f(g(a)) = 0, first find the values of yy where f(y)=0f(y) = 0. The numerator of f(y)=y242yf(y) = \frac{y^2 - 4}{2y} equals zero when y24=0y^2 - 4 = 0, yielding y=2y = 2 and y=2y = -2. Setting g(a)=3a1g(a) = 3a - 1 equal to these roots gives 3a1=2    a=13a - 1 = 2 \implies a = 1 and 3a1=2    a=1/33a - 1 = -2 \implies a = -1/3. Since aa must be positive, the correct value is 1.

Adım Adım Çözüm

1
Determine the values of the argument yy that satisfy f(y)=0f(y) = 0.
y=2y = 2 or y=2y = -2.
A fraction equals zero when its numerator is zero and its denominator is non-zero. Setting y24=0y^2 - 4 = 0 gives y=±2y = \pm 2.
2
Substitute g(a)=3a1g(a) = 3a - 1 into yy to solve for aa.
Solving 3a1=23a - 1 = 2 yields a=1a = 1; solving 3a1=23a - 1 = -2 yields a=1/3a = -1/3.
Setting the expression for g(a)g(a) equal to each root of f(y)=0f(y) = 0 identifies all potential values for aa.
3
Select the value of aa matching the positivity condition.
a=1a = 1.
The question explicitly specifies finding the positive value of aa.

Anahtar Kavram

Function composition and evaluation of nested functional equations.
Soru 698Soru

At a bio-tech research facility, the ratio of male to female scientists is initially 5:35 : 3. After 44 female scientists leave and 1212 male scientists join the facility, the ratio of male to female scientists becomes 4:14 : 1. If a group of NN additional female scientists subsequently joins the facility, changing the ratio of male to female scientists to 8:58 : 5, what is the value of NN?

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Cevap: 12

Cevap

The value of NN is 12.
By setting up ratio equations stage-by-stage using multiplier kk, we determine that k=4k = 4, yielding 32 male and 8 female scientists after the first change. Solving 328+N=85\frac{32}{8+N} = \frac{8}{5} yields N=12N = 12.

Adım Adım Çözüm

1
Define initial variables using a common ratio multiplier kk.
Male scientists = 5k5k, Female scientists = 3k3k.
Ratios preserve proportionality through a constant multiplier.
2
Formulate and solve the equation for the first population adjustment.
5k+123k4=4    5k+12=12k16    7k=28    k=4\frac{5k + 12}{3k - 4} = 4 \implies 5k + 12 = 12k - 16 \implies 7k = 28 \implies k = 4.
Adding 12 males and removing 4 females sets the new ratio to 4:14 : 1.
3
Determine the exact number of male and female scientists at the facility after the first adjustment.
Male scientists = 5(4)+12=325(4) + 12 = 32; Female scientists = 3(4)4=83(4) - 4 = 8.
Substitute k=4k = 4 back into the adjusted quantity expressions.
4
Formulate and solve the equation for the second population adjustment involving NN.
328+N=85    8(8+N)=160    64+8N=160    8N=96    N=12\frac{32}{8 + N} = \frac{8}{5} \implies 8(8 + N) = 160 \implies 64 + 8N = 160 \implies 8N = 96 \implies N = 12.
The number of male scientists remains 32 while female scientists increase by NN to achieve an 8:58 : 5 ratio.

Anahtar Kavram

Multi-step ratio manipulation and algebraic modeling
Tahmini Süre:2m 0s
Soru 699Soru

For all non-zero real numbers aa and bb, the binary operator \diamond is defined by ab=abaa \diamond b = a - \frac{b}{a}. If kk is a positive integer such that (k3)3=12(k \diamond 3) \diamond 3 = \frac{1}{2}, what is the value of kk?

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Cevap: 3

Cevap

The positive integer value of kk is 3.
Applying the non-commutative custom operator definition ab=abaa \diamond b = a - \frac{b}{a} to the nested expression (k3)3=12(k \diamond 3) \diamond 3 = \frac{1}{2} requires working from the inside out. Letting u=k3=k3ku = k \diamond 3 = k - \frac{3}{k}, the outer equation becomes u3=u3u=12u \diamond 3 = u - \frac{3}{u} = \frac{1}{2}. Multiplying through by 2u2u gives 2u2u6=02u^2 - u - 6 = 0, which factors as (2u+3)(u2)=0(2u + 3)(u - 2) = 0, yielding u=2u = 2 or u=32u = -\frac{3}{2}. Substituting u=2u = 2 back into k3k=2k - \frac{3}{k} = 2 produces k22k3=0k^2 - 2k - 3 = 0, which factors as (k3)(k+1)=0(k - 3)(k + 1) = 0. Since kk must be a positive integer, k=3k = 3. Testing u=32u = -\frac{3}{2} gives 2k2+3k6=02k^2 + 3k - 6 = 0, which has no integer solutions.

Adım Adım Çözüm

1
Substitute a temporary variable for the inner custom operator expression.
Let u=k3=k3ku = k \diamond 3 = k - \frac{3}{k}.
Simplifies the nested expression (k3)3=12(k \diamond 3) \diamond 3 = \frac{1}{2} to a single variable operation u3=12u \diamond 3 = \frac{1}{2}.
2
Apply the operator definition to u3u \diamond 3 and solve the resulting quadratic equation for uu.
u3u=12    2u2u6=0    (2u+3)(u2)=0u - \frac{3}{u} = \frac{1}{2} \implies 2u^2 - u - 6 = 0 \implies (2u + 3)(u - 2) = 0, so u=2u = 2 or u=32u = -\frac{3}{2}.
Clearing the denominator uu transforms the custom operator equation into a standard quadratic equation.
3
Solve for positive integer kk using the obtained values of uu.
Setting k3k=2k - \frac{3}{k} = 2 yields k22k3=0    (k3)(k+1)=0k^2 - 2k - 3 = 0 \implies (k - 3)(k + 1) = 0. Since kk must be a positive integer, k=3k = 3. Setting k3k=32k - \frac{3}{k} = -\frac{3}{2} yields 2k2+3k6=02k^2 + 3k - 6 = 0, which has non-integer discriminant 57\sqrt{57}.
Only u=2u = 2 yields an integer solution for kk, satisfying all problem constraints.

Anahtar Kavram

Custom Operator Evaluation and Nested Functional Equations
Soru 700Soru

For all non-zero real numbers xx, the function ff satisfies the equation 2f(x)+f(1x)=6x2f(x) + f\left(\frac{1}{x}\right) = 6x. What is the value of f(2)f(2)?

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Cevap: 7

Cevap

The value of f(2)f(2) is 7.
Substituting x=2x = 2 into the functional equation gives 2f(2)+f(12)=122f(2) + f\left(\frac{1}{2}\right) = 12. Substituting x=12x = \frac{1}{2} gives 2f(12)+f(2)=32f\left(\frac{1}{2}\right) + f(2) = 3. Multiplying the first equation by 2 and subtracting the second equation eliminates f(12)f\left(\frac{1}{2}\right), producing 3f(2)=213f(2) = 21, so f(2)=7f(2) = 7.

Adım Adım Çözüm

1
Substitute x=2x = 2 into the functional equation
2f(2)+f(12)=122f(2) + f\left(\frac{1}{2}\right) = 12
This establishes a linear relation between f(2)f(2) and f(12)f\left(\frac{1}{2}\right).
2
Substitute x=12x = \frac{1}{2} into the functional equation
2f(12)+f(2)=32f\left(\frac{1}{2}\right) + f(2) = 3
This establishes a second linear relation involving the reciprocal input.
3
Eliminate f(12)f\left(\frac{1}{2}\right) by solving the system of equations
f(2)=7f(2) = 7
Multiplying the first equation by 2 yields 4f(2)+2f(12)=244f(2) + 2f\left(\frac{1}{2}\right) = 24. Subtracting the second equation gives 3f(2)=213f(2) = 21, which simplifies to f(2)=7f(2) = 7.

Anahtar Kavram

Evaluating functional equations by reciprocal variable substitution to form and solve a linear system.
Tahmini Süre:2m 0s
ÖncekiSayfa 35 / 110Sonraki
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