Tüm alıştırma soruları

2789 soru

Soru 2001Soru

A solid sphere has a volume of 36π36\pi cubic centimeters. What is the radius, in centimeters, of the sphere?

Cevabı ve açıklamayı göster

Cevap: 3

Cevap

The radius of the sphere is 3 centimeters.
The volume of a sphere is given by the formula V=43πr3V = \frac{4}{3}\pi r^3. Substituting 36π36\pi for VV gives 36π=43πr336\pi = \frac{4}{3}\pi r^3. Dividing both sides by π\pi results in 36=43r336 = \frac{4}{3}r^3. Multiplying both sides by 34\frac{3}{4} yields 27=r327 = r^3. Taking the cube root of both sides gives r=3r = 3. Thus, the radius of the sphere is 3 centimeters.

Adım Adım Çözüm

1
State the sphere volume formula.
V=43πr3V = \frac{4}{3}\pi r^3
The volume of a sphere is calculated using this standard formula relating volume to radius.
2
Substitute the given volume value into the formula.
36π=43πr336\pi = \frac{4}{3}\pi r^3
The problem specifies the volume is 36π36\pi cubic centimeters.
3
Solve for the radius cubed (r3r^3).
r3=27r^3 = 27
Dividing both sides of the equation by π\pi yields 36=43r336 = \frac{4}{3}r^3, and multiplying both sides by 34\frac{3}{4} isolates r3r^3 to give 27.
4
Take the cube root of both sides to find the radius (rr).
r=3r = 3
The cube root of 27 is 3, since 3×3×3=273 \times 3 \times 3 = 27.

Anahtar Kavram

Using the volume of a sphere formula to solve for an unknown radius.
Soru 2002Soru

A fitness center surveyed a random sample of its members about their primary workout time and their membership type. The results of the survey are partially shown in the table below.

Primary Workout TimeBasic MembershipPremium MembershipTotal
Morning6060aa
Afternoonbb20206060
Evening6060140140
Total180180300300

Given that a randomly selected member from this survey has a Basic membership, what is the probability that this member's primary workout time is in the evening?

Cevabı ve açıklamayı göster

Cevap: 49\frac{4}{9}

Cevap

49\frac{4}{9}
To find the probability that a randomly selected member's primary workout time is in the evening given that they have a Basic membership, we restrict the denominator to the total number of Basic members, which is 180180. The number of Basic members who work out in the afternoon is 6020=4060 - 20 = 40. Subtracting the morning (6060) and afternoon (4040) Basic members from the total Basic members (180180) yields 1806040=80180 - 60 - 40 = 80 Basic members who work out in the evening. The probability is 80180\frac{80}{180}, which simplifies to 49\frac{4}{9}.

Adım Adım Çözüm

1
Find the total number of members with a Premium membership.
The total number of Premium members is 120120.
The grand total of surveyed members is 300300, and the total number of Basic members is 180180. Subtracting the Basic members from the grand total gives the Premium members: 300180=120300 - 180 = 120.
2
Find the value of bb, which is the number of Basic members whose primary workout time is in the afternoon.
b=40b = 40
The total number of members who work out in the afternoon is 6060, and 2020 of them have a Premium membership. Subtracting the Premium members from the afternoon total gives the Basic members: 6020=4060 - 20 = 40.
3
Find the number of Basic members whose primary workout time is in the evening.
There are 8080 Basic members who work out in the evening.
The total number of Basic members is 180180. Subtracting the Basic members who work out in the morning (6060) and afternoon (4040) from the total number of Basic members gives the remaining Basic members who work out in the evening: 1806040=80180 - 60 - 40 = 80.
4
Calculate the conditional probability that a randomly selected member works out in the evening, given they have a Basic membership.
The probability is 49\frac{4}{9}.
The condition restricts the sample space to the 180180 members with a Basic membership. Of these 180180 members, 8080 work out in the evening. The probability is the ratio of these two values: 80180=49\frac{80}{180} = \frac{4}{9}.

Anahtar Kavram

Conditional Probability in Two-Way Tables

Alternatif Yöntem

Instead of subtracting from the column total to find the missing Basic Evening value, one could first find all Premium values: the Premium Total is 300180=120300 - 180 = 120. Then, the Premium Morning value is 1202060=40120 - 20 - 60 = 40. This allows calculation of the Morning Total (60+40=10060 + 40 = 100). The Evening Total is given as 140140, and the Premium Evening value is 6060, which directly gives the Basic Evening value as 14060=80140 - 60 = 80. Finally, the probability is 80180=49\frac{80}{180} = \frac{4}{9}.
Tahmini Süre:2m 0s
Soru 2003Soru

At the beginning of 2015, City A and City B each had a daily water consumption of 1,200,0001,200,000 gallons. The daily water consumption of City A decreased linearly by 24,00024,000 gallons each year, and the daily water consumption of City B decreased exponentially by a constant percentage each year. At the beginning of 2025, the daily water consumption of City A was equal to the daily water consumption of City B. If these trends continue, what will be the daily water consumption of City B, in gallons, at the beginning of 2035?

Cevabı ve açıklamayı göster

Cevap: 768000

Cevap

768,000
To find the daily water consumption of City B at the beginning of 2035, we first determine the consumption of both cities at the beginning of 2025 (t=10t = 10 years after the beginning of 2015). For City A, which decreases linearly, the consumption is 1,200,00010×24,000=960,0001,200,000 - 10 \times 24,000 = 960,000 gallons. Since City B's consumption is equal to City A's at this time and decreases exponentially, we set up the equation 1,200,000b10=960,0001,200,000 \cdot b^{10} = 960,000, where bb is the annual decay factor. This gives b10=0.8b^{10} = 0.8. The consumption of City B at the beginning of 2035 (t=20t = 20) is given by 1,200,000b201,200,000 \cdot b^{20}. Using exponent rules, we can rewrite b20b^{20} as (b10)2(b^{10})^2. Substituting b10=0.8b^{10} = 0.8 gives 1,200,000(0.8)2=1,200,0000.64=768,0001,200,000 \cdot (0.8)^2 = 1,200,000 \cdot 0.64 = 768,000.

Adım Adım Çözüm

1
Calculate the consumption of City A at the beginning of 2025.
960,000960,000 gallons
City A decreases linearly by a constant 24,00024,000 gallons per year for 1010 years starting from 1,200,0001,200,000 gallons.
2
Set up the exponential model for City B at the beginning of 2025.
b10=0.8b^{10} = 0.8
City B's consumption decreases exponentially, so it is modeled by WB(t)=1,200,000btW_B(t) = 1,200,000 \cdot b^t. Since it equals City A's consumption at t=10t = 10, 1,200,000b10=960,0001,200,000 \cdot b^{10} = 960,000.
3
Determine the consumption of City B at the beginning of 2035.
768,000768,000 gallons
At the beginning of 2035 (t=20t = 20), City B's consumption is 1,200,000b201,200,000 \cdot b^{20}. Since b20=(b10)2b^{20} = (b^{10})^2, we substitute 0.80.8 for b10b^{10} to get 1,200,000(0.8)2=1,200,0000.64=768,0001,200,000 \cdot (0.8)^2 = 1,200,000 \cdot 0.64 = 768,000.

Anahtar Kavram

Distinguishing between linear and exponential models and applying exponent properties to solve exponential growth/decay problems.

Alternatif Yöntem

Alternatively, you can solve for the annual decay factor bb directly using a calculator. Since b10=0.8b^{10} = 0.8, we take the 10th root of both sides to get b=0.80.10.97793b = 0.8^{0.1} \approx 0.97793. The water consumption at t=20t = 20 is then calculated as 1,200,000(0.97793)20768,0001,200,000 \cdot (0.97793)^{20} \approx 768,000 gallons. Recognizing the algebraic shortcut (b10)2=b20(b^{10})^2 = b^{20} avoids decimal approximations and is much faster.
Tahmini Süre:2m 30s
Soru 2004Soru

The population of a species of fish in a lake can be modeled by the function P(t)=P02tdP(t) = P_0 \cdot 2^{\frac{t}{d}}, where P0P_0 is the initial population when the population was first measured, tt represents the time in years since it was first measured, and dd is a constant representing the doubling time in years. If the population of the fish doubles every 6 years, and the population after 18 years is 3,200, what was the initial population of the fish?

Cevabı ve açıklamayı göster

Cevap: 400

Cevap

The initial population of the fish was 400.
By substituting the doubling time d=6d = 6 and the final population of 3,200 at t=18t = 18 into the exponential model P(t)=P02tdP(t) = P_0 \cdot 2^{\frac{t}{d}}, we get 3,200=P021863,200 = P_0 \cdot 2^{\frac{18}{6}}. Simplifying the exponent gives 3,200=P0233,200 = P_0 \cdot 2^3, which simplifies further to 3,200=8P03,200 = 8P_0. Dividing both sides by 8 yields P0=400P_0 = 400.

Adım Adım Çözüm

1
Identify the values for the known variables from the word problem.
d=6d = 6 years and at t=18t = 18 years, P(18)=3,200P(18) = 3,200.
To substitute these values into the exponential growth function model.
2
Substitute the known values into the exponential function P(t)=P02tdP(t) = P_0 \cdot 2^{\frac{t}{d}}.
3,200=P021863,200 = P_0 \cdot 2^{\frac{18}{6}}
To set up an equation to solve for the unknown parameter P0P_0.
3
Simplify the exponent and calculate the growth factor.
3,200=P0233,200=8P03,200 = P_0 \cdot 2^3 \Rightarrow 3,200 = 8P_0
Reducing the fractional exponent simplifies the equation.
4
Solve for the initial population P0P_0 by dividing both sides of the equation by 8.
P0=400P_0 = 400
Isolating P0P_0 gives the initial population of the fish.

Anahtar Kavram

Using an exponential function to model real-world growth and solving for the initial value.
Soru 2005Soru

A right circular cylindrical tank with a base radius of 4 inches4\text{ inches} contains water. A solid metal sphere with a radius of 3 inches3\text{ inches} is completely submerged in the water, causing the water level to rise. If no water overflows from the tank, what is the increase, in inches, in the water level of the tank?

Cevabı ve açıklamayı göster

Cevap: 2.25

Cevap

2.25
The correct answer is 2.25. The volume of the submerged sphere is calculated using the formula V=43πr3V = \frac{4}{3}\pi r^3. With a radius of 3 inches3\text{ inches}, the volume is V=43π(3)3=36π cubic inchesV = \frac{4}{3}\pi (3)^3 = 36\pi\text{ cubic inches}. The volume of the displaced water is represented by a cylinder of radius 4 inches4\text{ inches} and height hh, which represents the increase in water level. The volume of this displaced cylinder is V=π(4)2h=16πhV = \pi (4)^2 h = 16\pi h. Since the volume of the displaced water is equal to the volume of the submerged sphere, we set them equal: 16πh=36π16\pi h = 36\pi. Dividing both sides by 16π16\pi yields h=2.25h = 2.25.

Adım Adım Çözüm

1
Calculate the volume of the solid metal sphere using the formula V=43πr3V = \frac{4}{3}\pi r^3 with radius r=3 inchesr = 3\text{ inches}.
Vsphere=43π(3)3=36π cubic inchesV_{\text{sphere}} = \frac{4}{3}\pi (3)^3 = 36\pi\text{ cubic inches}
The volume of the sphere represents the total volume of water that will be displaced when the sphere is completely submerged.
2
Express the volume of the displaced water in the cylinder as a function of the rise in water level, hh.
Vdisplaced=π(4)2h=16πh cubic inchesV_{\text{displaced}} = \pi (4)^2 h = 16\pi h\text{ cubic inches}
The displaced water forms a cylindrical shape with the same base radius as the tank (4 inches4\text{ inches}) and a height equal to the change in the water level (hh).
3
Equate the volume of the displaced water to the volume of the sphere and solve for hh.
16πh=36πh=3616=2.25 inches16\pi h = 36\pi \Rightarrow h = \frac{36}{16} = 2.25\text{ inches}
By Archimedes' principle, the volume of the displaced water must equal the volume of the fully submerged solid sphere.

Anahtar Kavram

Equating the volume of a submerged object to the volume of displaced liquid in a cylindrical container.
Tahmini Süre:2m 0s
Soru 2006Soru

If 8x+1=(14)2x38^{x + 1} = \left(\frac{1}{4}\right)^{2x - 3}, what is the value of xx?

Cevabı ve açıklamayı göster

Cevap: 37\frac{3}{7}

Cevap

37\frac{3}{7}
To solve the equation, we rewrite both bases using the common base 22. Because 8=238 = 2^3, the left side simplifies to (23)x+1=23x+3(2^3)^{x + 1} = 2^{3x + 3}. Because 14=22\frac{1}{4} = 2^{-2}, the right side simplifies to (22)2x3=24x+6(2^{-2})^{2x - 3} = 2^{-4x + 6}. Since the bases are now identical, their exponents must be equal: 3x+3=4x+63x + 3 = -4x + 6. Solving this linear equation by adding 4x4x to both sides gives 7x+3=67x + 3 = 6. Subtracting 33 from both sides gives 7x=37x = 3. Dividing by 77 yields the value of 37\frac{3}{7}.

Adım Adım Çözüm

1
Express both sides of the equation using a common base of 22.
23(x+1)=22(2x3)2^{3(x + 1)} = 2^{-2(2x - 3)}
Since 8=238 = 2^3 and 14=22\frac{1}{4} = 2^{-2}, we can rewrite the terms with the same base to solve the exponential equation.
2
Apply the distributive property to simplify the exponents.
23x+3=24x+62^{3x + 3} = 2^{-4x + 6}
Multiplying the outer exponent by each term inside the parentheses simplifies the expression.
3
Set the exponents equal to each other and solve the linear equation for xx.
3x+3=4x+6    7x=3    x=373x + 3 = -4x + 6 \implies 7x = 3 \implies x = \frac{3}{7}
When bases are equal and positive (and not 1), their exponents must be equal.

Anahtar Kavram

Solving exponential equations by expressing both sides with a common base and equating exponents.
Soru 2007Soru

A technology company surveyed a random sample of 128128 of its employees to determine their primary operating system and their job role. The table below summarizes the results of the survey.

Job RolemacOSWindowsTotal
Developer303050508080
Designer303018184848
Total60606868128128

If an employee from the survey whose job role is developer is selected at random, what is the probability that the employee's primary operating system is Windows?

Cevabı ve açıklamayı göster

Cevap: 0.625

Cevap

5/8 (or 0.625)
The question asks for the probability that a randomly selected employee uses Windows, given that their job role is developer. This restricts the sample space to only the developers. From the table, there are 8080 total developers, which serves as the denominator. Within this group of developers, 5050 use Windows, which serves as the numerator. The probability is 5080\frac{50}{80}, which simplifies to 58\frac{5}{8} or 0.6250.625. Both 5/85/8 and .625.625 are correct formats that fit the standard SAT grid-in requirements.

Adım Adım Çözüm

1
Identify the subgroup defined by the condition.
The total number of developers is 8080.
The probability is conditional on the employee being a developer, which restricts the denominator of the probability to the total number of developers.
2
Identify the favorable outcomes within the subgroup.
There are 5050 developers whose primary operating system is Windows.
This value represents the numerator for our conditional probability calculation.
3
Calculate the conditional probability.
The probability is 5080=58\frac{50}{80} = \frac{5}{8} (or 0.6250.625).
Dividing the favorable outcomes by the total outcomes in the restricted sample space gives the correct conditional probability.

Anahtar Kavram

Conditional Probability in Two-Way Tables
Soru 2008Soru

In the equation (2x3)(x+4)=k(2x - 3)(x + 4) = k, kk is a constant. If x=2x = 2 is a solution to the equation, what is the other solution to the equation?

Cevabı ve açıklamayı göster

Cevap: 92-\frac{9}{2}

Cevap

92-\frac{9}{2}
Substituting the known solution x=2x = 2 into the equation (2x3)(x+4)=k(2x - 3)(x + 4) = k yields (2(2)3)(2+4)=k(2(2) - 3)(2 + 4) = k, which simplifies to (1)(6)=k(1)(6) = k, so k=6k = 6. Substituting this value back into the equation gives (2x3)(x+4)=6(2x - 3)(x + 4) = 6. Expanding the left side yields 2x2+5x12=62x^2 + 5x - 12 = 6. Subtracting 6 from both sides places the quadratic equation in standard form: 2x2+5x18=02x^2 + 5x - 18 = 0. Since x=2x = 2 is a root, (x2)(x - 2) is a factor. Factoring the quadratic gives (x2)(2x+9)=0(x - 2)(2x + 9) = 0. Setting the second factor equal to zero, 2x+9=02x + 9 = 0, yields the other solution, x=92x = -\frac{9}{2}.

Adım Adım Çözüm

1
Substitute the known solution x=2x = 2 into the equation to solve for kk.
k=6k = 6
Since x=2x = 2 is a solution, it must satisfy the equation (2(2)3)(2+4)=k(2(2) - 3)(2 + 4) = k, which simplifies to (1)(6)=k(1)(6) = k.
2
Substitute k=6k = 6 back into the original equation, expand the binomial product, and write the quadratic equation in standard form.
2x2+5x18=02x^2 + 5x - 18 = 0
Expanding the binomials gives 2x2+5x12=62x^2 + 5x - 12 = 6. Subtracting 6 from both sides yields the standard form quadratic equation 2x2+5x18=02x^2 + 5x - 18 = 0.
3
Factor the quadratic equation to find the other root.
(x2)(2x+9)=0(x - 2)(2x + 9) = 0, yielding x=2x = 2 and x=92x = -\frac{9}{2}
Since x=2x = 2 is a solution, (x2)(x - 2) must be a factor. Dividing the quadratic by (x2)(x - 2) yields the other factor, (2x+9)(2x + 9).

Anahtar Kavram

Solving quadratic equations by substituting a known root to determine constants, then rewriting and factoring the equation.

Alternatif Yöntem

Another way to find the other solution is to use the relationship between the coefficients of a quadratic equation and its roots. Once the equation is written in standard form as 2x2+5x18=02x^2 + 5x - 18 = 0, the sum of the roots is given by ba=52-\frac{b}{a} = -\frac{5}{2}. Since one root is 22, the other root rr must satisfy 2+r=522 + r = -\frac{5}{2}, which simplifies to r=522=92r = -\frac{5}{2} - 2 = -\frac{9}{2}.
Tahmini Süre:1m 30s
Soru 2009Soru
An equation is shown below.
x+2x14x=4x2x\frac{x+2}{x-1} - \frac{4}{x} = \frac{4}{x^2 - x}

What is the real solution to the equation above?

Cevabı ve açıklamayı göster

Cevap: 2

Cevap

The only real solution to the equation is 22.
To solve the rational equation, we multiply all terms by the common denominator x(x1)x(x-1), assuming x0x \neq 0 and x1x \neq 1. This results in the equation x(x+2)4(x1)=4x(x+2) - 4(x-1) = 4. Expanding and simplifying this gives x2+2x4x+4=4x^2 + 2x - 4x + 4 = 4, which simplifies to x22x=0x^2 - 2x = 0. Factoring the quadratic expression yields x(x2)=0x(x-2) = 0, which gives the potential solutions x=0x = 0 and x=2x = 2. However, substituting x=0x = 0 back into the original equation causes a division by zero. Therefore, x=0x = 0 is an extraneous solution, and the only valid real solution is 22.

Adım Adım Çözüm

1
Find the common denominator for the terms in the rational equation.
The common denominator is x(x1)=x2xx(x-1) = x^2 - x, which requires x0x \neq 0 and x1x \neq 1.
Multiplying by the common denominator allows us to eliminate the fractions.
2
Multiply every term in the equation by the common denominator x(x1)x(x-1) and simplify.
x(x+2)4(x1)=4x(x+2) - 4(x-1) = 4
This clears the denominators and converts the rational equation into a polynomial equation.
3
Expand and simplify the resulting equation to standard quadratic form.
x2+2x4x+4=4x^2 + 2x - 4x + 4 = 4, which simplifies to x22x=0x^2 - 2x = 0.
Grouping like terms is necessary to solve the quadratic equation.
4
Factor the quadratic equation to determine the potential solutions.
x(x2)=0x(x-2) = 0, giving potential solutions of x=0x = 0 and x=2x = 2.
Factoring allows us to find the roots of the quadratic expression.
5
Check the potential solutions in the original equation to identify any extraneous solutions.
x=0x = 0 is extraneous because it leads to division by zero. Thus, the only real solution is x=2x = 2.
Solutions that make any denominator in the original equation equal to zero must be excluded.

Anahtar Kavram

Solving rational equations and identifying extraneous solutions
Soru 2010Soru

Which choice completes the text with the most logical and precise word or phrase?

Aşağıdaki boşlukları doldurun

In the mid-twentieth century, the emergence of Abstract Expressionism was often characterized by critics as a sudden and complete rupture from traditional representation. However, art historian Clement Greenberg argued that the movement was actually a logical of Western painting’s historical trajectory toward flatness, rather than a rejection of it.
Cevabı ve açıklamayı göster

Cevap

The correct word to fill the blank is 'outgrowth' (or similar synonyms like 'continuation', 'evolution', or 'extension').
The text sets up a contrast between critics who saw Abstract Expressionism as a 'rupture' (a break) from the past, and Clement Greenberg, who argued that it was a natural development of Western painting's trajectory. The blank requires a word that indicates a natural development or result arising from a previous state. Words like 'outgrowth,' 'continuation,' 'evolution,' and 'extension' logically complete the text by indicating that Abstract Expressionism was a direct result of earlier artistic trends.

Adım Adım Çözüm

1
Analyze the context of the sentence containing the blank to determine the logical relationship.
The first sentence describes Abstract Expressionism as a 'rupture' from tradition, but the second sentence uses 'However' to contrast this view, presenting Greenberg's argument that it is actually a logical progression.
This establishes that the word in the blank must mean a development or continuation, not a break.
2
Identify the word that completes the text with the most logical and precise meaning.
The word 'outgrowth' (or related words like 'continuation', 'evolution', 'extension') perfectly fits, describing a natural development from an existing trajectory.
It maintains consistency with the idea that the movement was a development of Western painting rather than a rejection of it.

Anahtar Kavram

Words in Context: High-Utility Vocabulary
Tahmini Süre:1m 0s
Soru 2011Soru

An electric delivery van's remaining battery capacity, BB, in kilowatt-hours (kWh), after driving dd miles is modeled by a linear equation. After driving 4545 miles, the remaining battery capacity is 6868 kWh. After driving a total of 120120 miles, the remaining battery capacity is 3838 kWh. According to this model, how many miles can the van drive on a full charge before the battery capacity reaches 00 kWh?

Cevabı ve açıklamayı göster

Cevap: 215

Cevap

215
To find the maximum distance the van can drive on a full charge, we model the relationship between the remaining battery capacity, BB, and the distance driven, dd, using the linear equation B=md+B0B = md + B_0. First, calculate the rate of consumption (slope, mm) using the points (45,68)(45, 68) and (120,38)(120, 38): m=386812045=3075=0.4m = \frac{38 - 68}{120 - 45} = \frac{-30}{75} = -0.4 kWh per mile. Next, find the initial battery capacity (B0B_0) by substituting the values from one of the points: 68=0.4(45)+B068 = -0.4(45) + B_0, which simplifies to 68=18+B068 = -18 + B_0, so B0=86B_0 = 86 kWh. Finally, determine the distance dd when the battery is fully depleted (B=0B = 0): 0=0.4d+860 = -0.4d + 86, which yields 0.4d=860.4d = 86, and d=215d = 215 miles.

Adım Adım Çözüm

1
Calculate the rate of change of the battery capacity per mile driven.
The rate of change (slope) is 0.4-0.4 kWh per mile.
The slope mm represents the energy consumption rate and is calculated using the two data points (45,68)(45, 68) and (120,38)(120, 38) with the formula m=386812045=3075=0.4m = \frac{38 - 68}{120 - 45} = \frac{-30}{75} = -0.4.
2
Determine the initial battery capacity when the distance driven is 0 miles.
The initial battery capacity is 8686 kWh.
Using the slope-intercept form B=md+B0B = md + B_0, substitute m=0.4m = -0.4 and the point (45,68)(45, 68) to get 68=0.4(45)+B068 = -0.4(45) + B_0. This simplifies to 68=18+B068 = -18 + B_0, so B0=86B_0 = 86.
3
Solve for the distance driven dd when the battery capacity BB is 00 kWh.
The distance is 215215 miles.
Set B=0B = 0 in the linear model B=0.4d+86B = -0.4d + 86 to get 0=0.4d+860 = -0.4d + 86. Solving for dd gives 0.4d=860.4d = 86, which results in d=860.4=215d = \frac{86}{0.4} = 215.

Anahtar Kavram

Interpreting and calculating slope, y-intercept, and x-intercept of a linear function in a real-world context.
Soru 2012Soru

For the inequality 2(3x4)+5>3x12-2(3x - 4) + 5 > -3x - 12, which inequality represents all possible values of xx?

Cevabı ve açıklamayı göster

Cevap: x<253x < \frac{25}{3}

Cevap

x<253x < \frac{25}{3}
The correct inequality is obtained by first distributing 2-2 to the terms inside the parentheses to get 6x+8+5>3x12-6x + 8 + 5 > -3x - 12. Combining the constants on the left yields 6x+13>3x12-6x + 13 > -3x - 12. Adding 3x3x to both sides results in 3x+13>12-3x + 13 > -12, and subtracting 13 from both sides gives 3x>25-3x > -25. Finally, dividing by 3-3 and flipping the inequality sign results in the correct solution.

Adım Adım Çözüm

1
Distribute 2-2 to the terms inside the parentheses on the left side of the inequality.
6x+8+5>3x12-6x + 8 + 5 > -3x - 12
Applying the distributive property simplifies the expression.
2
Combine the constant terms on the left side.
6x+13>3x12-6x + 13 > -3x - 12
Simplifying the constant terms makes it easier to isolate the variable.
3
Add 3x3x to both sides to move all variable terms to the left side.
3x+13>12-3x + 13 > -12
This isolates the variable terms on one side of the inequality.
4
Subtract 13 from both sides to isolate the variable term.
3x>25-3x > -25
This isolates the term containing xx.
5
Divide both sides by 3-3 and reverse the direction of the inequality sign.
x<253x < \frac{25}{3}
Dividing by a negative number requires reversing the inequality sign.

Anahtar Kavram

Solving linear inequalities in one variable using the distributive property and sign reversal rules.
Soru 2013Soru

A right square pyramid has a height of 9 centimeters9\text{ centimeters} and a square base with a side length of 5 centimeters5\text{ centimeters}. What is the volume, in cubic centimeters, of the pyramid?

Cevabı ve açıklamayı göster

Cevap: 75

Cevap

75
The volume of a right square pyramid is given by the formula V=13BhV = \frac{1}{3}Bh, where BB is the area of the base and hh is the height. Since the base is a square with side length 5 centimeters5\text{ centimeters}, its area is B=52=25 square centimetersB = 5^2 = 25\text{ square centimeters}. Substituting the base area and the height of 9 centimeters9\text{ centimeters} into the formula gives V=13×25×9=75 cubic centimetersV = \frac{1}{3} \times 25 \times 9 = 75\text{ cubic centimeters}.

Adım Adım Çözüm

1
Calculate the area of the square base (BB).
B=52=25 square centimetersB = 5^2 = 25\text{ square centimeters}
The base is a square with side length 5 centimeters5\text{ centimeters}, and the area of a square is calculated by squaring its side length.
2
Apply the volume formula for a pyramid: V=13BhV = \frac{1}{3}Bh.
V=13×25×9=75 cubic centimetersV = \frac{1}{3} \times 25 \times 9 = 75\text{ cubic centimeters}
Substituting the base area of 25 square centimeters25\text{ square centimeters} and the height of 9 centimeters9\text{ centimeters} into the pyramid volume formula yields the volume.

Anahtar Kavram

The volume of a pyramid is calculated using the formula V=13BhV = \frac{1}{3}Bh, where BB is the area of the base and hh is the height.
Tahmini Süre:45s
Soru 2014Soru

A technology company monitored the annual carbon emissions of its data centers. In 2025, the data centers' carbon emissions decreased by 12%12\% compared to the emissions in 2024. In 2026, the emissions were 387.2387.2 metric tons, which represented a 10%10\% increase compared to the emissions in 2025. What were the data centers' carbon emissions, in metric tons, in 2024?

Cevabı ve açıklamayı göster

Cevap: 400

Cevap

400
The correct answer is 400. To find the carbon emissions in 2024, we can set up the relationship using the variable EE for the 2024 emissions. A 12%12\% decrease in 2025 means the emissions were 0.88E0.88E. A 10%10\% increase in 2026 means the emissions were 1.10×0.88E=0.968E1.10 \times 0.88E = 0.968E. Since the 2026 emissions were 387.2387.2 metric tons, we solve 0.968E=387.20.968E = 387.2 to get E=400E = 400.

Adım Adım Çözüm

1
Set up an equation for the 2025 emissions in terms of the 2024 emissions (EE).
2025 emissions=E×(10.12)=0.88E2025\text{ emissions} = E \times (1 - 0.12) = 0.88E
The emissions in 2025 decreased by 12%12\% compared to the emissions in 2024.
2
Set up an equation for the 2026 emissions in terms of the 2025 emissions.
2026 emissions=2025 emissions×(1+0.10)=1.10×0.88E=0.968E2026\text{ emissions} = 2025\text{ emissions} \times (1 + 0.10) = 1.10 \times 0.88E = 0.968E
The emissions in 2026 represented a 10%10\% increase compared to the emissions in 2025.
3
Equate the expression for 2026 emissions to the given value and solve for EE.
0.968E=387.2    E=387.20.968=4000.968E = 387.2 \implies E = \frac{387.2}{0.968} = 400
The 2026 emissions are given as 387.2387.2 metric tons.

Anahtar Kavram

Solving multi-step percent change problems by working backward using the correct base values.

Alternatif Yöntem

Instead of setting up an algebraic equation, we can work backward step-by-step. First, find the 2025 emissions by reversing the 10%10\% increase from 2025 to 2026: 387.21.10=352\frac{387.2}{1.10} = 352 metric tons. Next, find the 2024 emissions by reversing the 12%12\% decrease from 2024 to 2025: 3520.88=400\frac{352}{0.88} = 400 metric tons.
Tahmini Süre:1m 15s
Soru 2015Soru

Two startup companies, Company X and Company Y, begin operations at the same time. At the start of operations (m=0m = 0), both companies have a monthly revenue of RR dollars.

* The monthly revenue of Company X increases by a constant amount of 0.12R0.12R dollars every 33 months.
* The monthly revenue of Company Y increases exponentially, growing by a constant percent of 6%6\% every 22 months.

Let X(m)X(m) and Y(m)Y(m) represent the monthly revenue of Company X and Company Y, respectively, after mm months of operation. Which of the following functions represents the ratio Y(m)X(m)\frac{Y(m)}{X(m)} for any positive integer mm that is a multiple of 66?

Cevabı ve açıklamayı göster

Cevap: (1.06)m21+0.04m\frac{(1.06)^{\frac{m}{2}}}{1 + 0.04m}

Cevap

The expression (1.06)m21+0.04m\frac{(1.06)^{\frac{m}{2}}}{1 + 0.04m}
The correct answer is the expression (1.06)m21+0.04m\frac{(1.06)^{\frac{m}{2}}}{1 + 0.04m}. This is found by representing the linear growth of Company X as X(m)=R(1+0.04m)X(m) = R(1 + 0.04m) because its revenue increases by a constant amount of 0.04R0.04R per month (since 0.12R0.12R every 3 months is 0.12R3=0.04R\frac{0.12R}{3} = 0.04R). The exponential growth of Company Y is represented as Y(m)=R(1.06)m2Y(m) = R(1.06)^{\frac{m}{2}} because its revenue increases by 6%6\% every 2 months, which yields a growth factor of 1.061.06 applied m2\frac{m}{2} times over mm months. The ratio Y(m)X(m)\frac{Y(m)}{X(m)} is then R(1.06)m2R(1+0.04m)\frac{R(1.06)^{\frac{m}{2}}}{R(1 + 0.04m)}, which simplifies to the correct expression after canceling the common factor RR.

Adım Adım Çözüm

1
Determine the expression for Company X's monthly revenue, X(m)X(m).
X(m)=R(1+0.04m)X(m) = R(1 + 0.04m)
Since Company X's revenue increases by a constant amount of 0.12R0.12R every 3 months, it grows linearly. The rate of increase per month is 0.12R3=0.04R\frac{0.12R}{3} = 0.04R dollars. Thus, after mm months, the revenue is X(m)=R+0.04Rm=R(1+0.04m)X(m) = R + 0.04R \cdot m = R(1 + 0.04m).
2
Determine the expression for Company Y's monthly revenue, Y(m)Y(m).
Y(m)=R(1.06)m2Y(m) = R(1.06)^{\frac{m}{2}}
Since Company Y's revenue grows by a constant percent of 6%6\% every 2 months, it grows exponentially. The growth factor for each 2-month period is 1+0.06=1.061 + 0.06 = 1.06. In mm months, the number of 2-month compounding periods is m2\frac{m}{2}. Therefore, the revenue is Y(m)=R(1.06)m2Y(m) = R(1.06)^{\frac{m}{2}}.
3
Find the ratio of Y(m)Y(m) to X(m)X(m).
Y(m)X(m)=(1.06)m21+0.04m\frac{Y(m)}{X(m)} = \frac{(1.06)^{\frac{m}{2}}}{1 + 0.04m}
Divide the expression for Y(m)Y(m) by the expression for X(m)X(m): Y(m)X(m)=R(1.06)m2R(1+0.04m)\frac{Y(m)}{X(m)} = \frac{R(1.06)^{\frac{m}{2}}}{R(1 + 0.04m)}. The constant initial revenue factor RR cancels out, simplifying to the final ratio.

Anahtar Kavram

Linear and Exponential Growth
Tahmini Süre:2m 30s
Soru 2016Soru

A solid metal right circular cylinder has a height of hh and a base radius of rr, where h>2rh > 2r. From one flat end of the cylinder, a hemisphere of radius rr is carved out. From the other flat end, a right circular cone of base radius rr and height h2rh - 2r is carved out. If the volume of the remaining solid is equal to the volume of a sphere with radius RR, which of the following equations represents RR in terms of rr and hh?

Cevabı ve açıklamayı göster

Cevap: R=r2h23R = \sqrt[3]{\frac{r^2 h}{2}}

Cevap

The correct equation is R=r2h23R = \sqrt[3]{\frac{r^2 h}{2}}
The volume of the cylinder is πr2h\pi r^2 h. Subtracting the hemisphere's volume (23πr3\frac{2}{3}\pi r^3) and the cone's volume (13πr2(h2r)=13πr2h23πr3\frac{1}{3}\pi r^2(h - 2r) = \frac{1}{3}\pi r^2 h - \frac{2}{3}\pi r^3) leaves a remaining volume of 23πr2h\frac{2}{3}\pi r^2 h. Setting this equal to the volume of a sphere of radius RR (43πR3\frac{4}{3}\pi R^3) gives 43πR3=23πr2h\frac{4}{3}\pi R^3 = \frac{2}{3}\pi r^2 h. Simplifying this equation yields R3=r2h2R^3 = \frac{r^2 h}{2}, and taking the cube root gives the correct relation.

Adım Adım Çözüm

1
Write the formula for the volume of the original cylinder.
Vcylinder=πr2hV_{\text{cylinder}} = \pi r^2 h
The volume of a cylinder with radius rr and height hh is given by the formula πr2h\pi r^2 h.
2
Write the volume formulas for the carved-out shapes.
Vhemisphere=23πr3V_{\text{hemisphere}} = \frac{2}{3}\pi r^3 and Vcone=13πr2(h2r)V_{\text{cone}} = \frac{1}{3}\pi r^2 (h - 2r)
A hemisphere is half a sphere, so its volume is 23πr3\frac{2}{3}\pi r^3. The volume of a cone with radius rr and height h2rh - 2r is 13πr2(h2r)\frac{1}{3}\pi r^2 (h - 2r).
3
Subtract the volumes of the carved-out shapes from the cylinder's volume.
Vremaining=πr2h23πr313πr2(h2r)=23πr2hV_{\text{remaining}} = \pi r^2 h - \frac{2}{3}\pi r^3 - \frac{1}{3}\pi r^2 (h - 2r) = \frac{2}{3}\pi r^2 h
Expanding the cone's volume gives 13πr2h23πr3\frac{1}{3}\pi r^2 h - \frac{2}{3}\pi r^3. Subtracting this and the hemisphere's volume from the cylinder's volume simplifies to 23πr2h\frac{2}{3}\pi r^2 h because the πr3\pi r^3 terms cancel out.
4
Equate the remaining volume to the volume of a sphere with radius RR and solve for RR.
43πR3=23πr2h    R3=r2h2    R=r2h23\frac{4}{3}\pi R^3 = \frac{2}{3}\pi r^2 h \implies R^3 = \frac{r^2 h}{2} \implies R = \sqrt[3]{\frac{r^2 h}{2}}
Equating the remaining volume to the volume of a sphere of radius RR and dividing both sides by 23π\frac{2}{3}\pi gives 2R3=r2h2 R^3 = r^2 h. Dividing by 2 and taking the cube root isolates RR.

Anahtar Kavram

Calculating and comparing volumes of combined geometric solids and algebraically isolating variables.
Tahmini Süre:3m 0s
Soru 2017Soru

Acoustic ecologist Bernie Krause coined the term "biophony" to describe the collective sound landscape produced by all living organisms in a given habitat. In a healthy ecosystem, animal species partition their vocalizations across different frequencies and time slots to avoid overlapping with one another ______ acoustic niche hypothesis suggests that vocal space is as limited and contested as physical space.

Which choice completes the text so that it conforms to the conventions of Standard English?

Cevabı ve açıklamayı göster

Cevap: ; this

Cevap

; this
The correct option correctly uses a semicolon to separate two independent clauses. The clause preceding the blank and the clause succeeding the blank are both independent, meaning they contain their own subjects and verbs and can stand alone as complete thoughts. A semicolon is a grammatically standard way to link such closely related clauses.

Adım Adım Çözüm

1
Identify the clause boundaries within the sentence.
The text contains two independent clauses: 'In a healthy ecosystem, animal species partition their vocalizations across different frequencies and time slots to avoid overlapping with one another' and 'this acoustic niche hypothesis suggests that vocal space is as limited and contested as physical space.'
Locating the boundaries of the independent clauses helps determine what punctuation or conjunction is necessary to connect them.
2
Analyze the logical relationship between the two independent clauses.
The second clause explains and supports the observation made in the first clause. There is no contrast between them.
Understanding the logical connection prevents the selection of inappropriate coordinators or subordinators.
3
Determine the grammatically correct way to link the independent clauses.
Independent clauses must be separated by a period, a semicolon, a colon, or a comma followed by a coordinating conjunction (such as 'and'). A semicolon followed by the pronoun 'this' correctly links them.
Applying standard English conventions to eliminate grammatical errors like comma splices and run-ons.

Anahtar Kavram

Clause Boundaries and Linking
Soru 2018Soru

For a real number xx, the equation 3x+10=x+2\sqrt{3x + 10} = x + 2 is given. What is the value of the expression x1x - 1?

Cevabı ve açıklamayı göster

Cevap: 1

Cevap

The correct answer is the value 1, which is obtained by evaluating the expression for the only valid solution to the equation.
To solve the given radical equation, square both sides to obtain a quadratic equation, which simplifies to x2+x6=0x^2 + x - 6 = 0. Factoring this equation yields potential solutions of x=2x = 2 and x=3x = -3. Substituting x=2x = 2 back into the original equation produces a true statement, confirming it as a valid solution. Substituting x=3x = -3 results in an inequality, identifying it as an extraneous solution. Evaluating the expression for the valid solution yields 21=12 - 1 = 1.

Adım Adım Çözüm

1
Eliminate the radical by squaring both sides of the equation.
3x+10=(x+2)23x + 10 = (x + 2)^2, which expands to 3x+10=x2+4x+43x + 10 = x^2 + 4x + 4.
Squaring both sides removes the square root, allowing the equation to be solved algebraically.
2
Move all terms to one side to set the quadratic equation to zero.
x2+x6=0x^2 + x - 6 = 0.
A quadratic equation must be in the form ax2+bx+c=0ax^2 + bx + c = 0 to solve it by factoring.
3
Factor the quadratic equation.
(x+3)(x2)=0(x + 3)(x - 2) = 0, giving potential solutions of x=3x = -3 and x=2x = 2.
Factoring allows us to find the roots that satisfy the quadratic relationship.
4
Check both potential solutions in the original equation to identify any extraneous solutions.
For x=2x = 2, 3(2)+10=2+24=4\sqrt{3(2) + 10} = 2 + 2 \Rightarrow 4 = 4 (valid). For x=3x = -3, 3(3)+10=3+21=1\sqrt{3(-3) + 10} = -3 + 2 \Rightarrow 1 = -1 (invalid). Thus, x=3x = -3 is extraneous and x=2x = 2 is the only valid solution.
Squaring both sides of an equation can introduce extraneous roots that do not satisfy the original radical equation.
5
Evaluate the requested expression using the valid solution.
x1=21=1x - 1 = 2 - 1 = 1.
The question asks for the value of the expression rather than the value of the variable itself.

Anahtar Kavram

Radical and Rational Equations
Soru 2019Soru

A quality control analyst records the battery life, in hours, of 11 distinct prototype laptop batteries. The shortest battery life recorded is 10 hours, the median battery life is 50 hours, and the range of the battery lives is 74 hours. If each battery life is a whole number of hours, what is the maximum possible mean battery life, in hours, of the 11 prototypes?

Cevabı ve açıklamayı göster

Cevap: 60

Cevap

The maximum possible mean battery life of the 11 prototypes is 60 hours.
The maximum possible mean is achieved by maximizing the sum of the 11 distinct integers under the given constraints. By setting the elements below the median to the largest possible distinct integers less than 50 (46, 47, 48, 49) and the elements above the median to the largest possible distinct integers less than the maximum value of 84 (80, 81, 82, 83), we find the maximum sum to be 660. Dividing this sum by the 11 elements yields a maximum mean of 60.

Adım Adım Çözüm

1
Define the variable terms representing the sorted battery lives.
Let the 11 battery lives in sorted order be x1<x2<x3<x4<x5<x6<x7<x8<x9<x10<x11x_1 < x_2 < x_3 < x_4 < x_5 < x_6 < x_7 < x_8 < x_9 < x_{10} < x_{11}.
Establishing the order of elements helps apply the median and distinct integer constraints.
2
Identify the values of the minimum, maximum, and median elements.
The minimum value is x1=10x_1 = 10. The median of 11 elements is the 6th element, so x6=50x_6 = 50. The range is 74, which means the maximum value is x11=10+74=84x_{11} = 10 + 74 = 84.
These fixed values act as boundaries for the remaining elements.
3
Maximize the remaining elements under the distinct integer constraint.
To maximize the mean, we must maximize the sum S=x1+x2+x3+x4+x5+x6+x7+x8+x9+x10+x11S = x_1 + x_2 + x_3 + x_4 + x_5 + x_6 + x_7 + x_8 + x_9 + x_{10} + x_{11}. The elements below the median (x2,x3,x4,x5x_2, x_3, x_4, x_5) must be distinct integers strictly less than 50, so their maximum values are 46, 47, 48, and 49. The elements above the median (x7,x8,x9,x10x_7, x_8, x_9, x_{10}) must be distinct integers strictly less than 84, so their maximum values are 80, 81, 82, and 83.
Maximizing the individual elements maximizes the total sum, which in turn maximizes the mean.
4
Calculate the maximum sum and the resulting maximum mean.
The maximum sum is 10+46+47+48+49+50+80+81+82+83+84=66010 + 46 + 47 + 48 + 49 + 50 + 80 + 81 + 82 + 83 + 84 = 660. The maximum possible mean is 66011=60\frac{660}{11} = 60.
Dividing the maximum possible sum by the number of elements gives the maximum possible mean.

Anahtar Kavram

Maximizing the mean of a dataset with constraints on distinct values, median, and range.
Soru 2020Soru

A 3D printer uses a plastic filament at a constant rate of 2.5 grams2.5\text{ grams} per minute of printing time. The filament has a density of 1.25 grams per cubic centimeter1.25\text{ grams per cubic centimeter}. If the printer runs continuously for 4 hours4\text{ hours}, what is the total volume, in cubic centimeters, of the filament used?

Cevabı ve açıklamayı göster

Cevap: 480

Cevap

480
The correct answer is 480. First, convert the printing time from hours to minutes: 4 hours multiplied by 60 minutes per hour equals 240 minutes. Next, calculate the total mass of the filament used by multiplying the printing time by the usage rate: 240 minutes multiplied by 2.5 grams per minute equals 600 grams. Finally, convert the mass to volume by dividing the mass by the density: 600 grams divided by 1.25 grams per cubic centimeter equals 480 cubic centimeters.

Adım Adım Çözüm

1
Convert the printing time from hours to minutes.
240 minutes240\text{ minutes}
Since the filament consumption rate is given in grams per minute, the total time must be in minutes. Multiplying 4 hours4\text{ hours} by 60 minutes per hour60\text{ minutes per hour} yields 240 minutes240\text{ minutes}.
2
Calculate the total mass of the filament used.
600 grams600\text{ grams}
Multiplying the total printing time of 240 minutes240\text{ minutes} by the consumption rate of 2.5 grams per minute2.5\text{ grams per minute} gives a total mass of 600 grams600\text{ grams}.
3
Calculate the total volume of the filament used.
480 cubic centimeters480\text{ cubic centimeters}
Divide the total mass of 600 grams600\text{ grams} by the density of 1.25 grams per cubic centimeter1.25\text{ grams per cubic centimeter} to find the volume: 6001.25=480 cubic centimeters\frac{600}{1.25} = 480\text{ cubic centimeters}.

Anahtar Kavram

Multi-unit dimensional analysis involving rates, time, and density.
ÖncekiSayfa 101 / 140Sonraki
Tüm alıştırma soruları — SAT | Examkin