SAT Math : Percentage

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #12 : How To Find Percentage

If 10% of x is equal to 25% of y, and y=16, what is the value of x?

Possible Answers:

6.4

64

40

24

4

Correct answer:

40

Explanation:

Find 25% of y:

16 \cdot 0.25 = 4

10% of x is equal to 4. Therefore, 0.1x = 4.

Divide both sides by 0.1 to find that x = 40.

Example Question #31 : Percents

There are  registered students in the math club. Students are deciding what activity they could do for their end of semester event. They have three choices: rock climbing, bowling, or outdoor laser tag.  students vote for rock climbing,  students vote for bowling, and  students vote for outdoor laser tag.

What percent of students did not vote?

Possible Answers:

Correct answer:

Explanation:

The number of students who did not vote is:

The percent of students who did not vote is therefore:

 of the students did not vote.

Example Question #17 : How To Find Percentage

Joaquin is running for Prom King.  If he receives  of the votes from a senior class of  students, and  of the votes from a junior class of  students, how many votes did he receive in total?

Possible Answers:

Correct answer:

Explanation:

First, we find how many seniors voted for him:

0.30 * 200 = 60 seniors

Then we find how many juniors using the same method

0.60 * 250 = 150 Juniors

Finally, we add the two together

60 + 150 = 210 students total

Example Question #111 : Percentage

13 is what percent of 25? 

Possible Answers:

Correct answer:

Explanation:

To solve this problem, we should set up the following proportion

where x is the percentage we are looking for.

To solve, simply cross multiply and solve for x.

Therefore, our answer is 52%.

Example Question #19 : How To Find Percentage

What percent of  is

Possible Answers:

Correct answer:

Explanation:

Let's set up a proportion to solve this problem.

We're looking for a percentage, .

Our answer is 

Example Question #281 : Arithmetic

Classroom table

Jones Elementary School has seven eighth-grade teachers; each teacher has the number of boys and girls listed above. 

What percent of the students in eighth-grade are boys? Choose the closest answer.

Possible Answers:

Correct answer:

Explanation:

The number of boys adds up to

The number of girls adds up to

The total number of students is therefore .

The percent of the students that are boys is

,

making 48% the closest choice.

Example Question #112 : Percentage

What percent of  is ?

Possible Answers:

Correct answer:

Explanation:

We can set up a proportion to solve this problem. Remember that a percentage can be written as a fraction. 

Now we can cross-multiply to find our percent. 

Therefore, our answer is .

Example Question #115 : Percentage

Marisa and Ted are running for senior class president. 150 votes have been tallied so far; 88 for Marisa and 62 for Ted. If 250 students total are voting, how many more votes must Marisa win in order to defeat Ted and earn exactly 50% more votes than him? 

Possible Answers:

Correct answer:

Explanation:

For Marisa to earn 50% more votes than Ted, she will need to earn 1.5 times his amount of votes. If we call Ted's amount of votes x, and the total number of votes is 250, we can set up the equation:

If we combine like terms, we get:

And if we solve for x, we get: 

This means that Ted will get 100 votes. Since there are 250 votes total, we can figure out that Marisa will end up with 150 votes. 

The question asks "how many more votes must Marisa win in order to defeat Ted and earn exactly 50% more votes than him?" and tells us that Marisa already has 88 votes. 

, therefore, Marisa needs to earn 62 more votes. 

 

Example Question #113 : Percentage

What percent of  is ?

Possible Answers:

30\%

35\%

50\%

40\%

Correct answer:

30\%

Explanation:

This question involves the verbal cues "of" and "is."  "Of" means to multiply and "is" means equal. 

Thus the equation to solve becomes:  0.01P\times 150=45.

Example Question #22 : Percentage

If there is a 10% sale on an item, and then 9% sales tax is applied to that after-sale price, then what is the total cost of the item including tax as a percentage of its pre-sale sticker price?

Possible Answers:

101%

99%

81.9%

98.1%

99.2%

Correct answer:

98.1%

Explanation:

A 10% sale means that the post-sale price of the item is now 90%, or 0.9 of the original cost of the item. We then apply 9% sales tax by multiplying the 0.9 by 109%, or 1.09. 0.9 * 1.09 = .981, so the total cost of the item is 98.1% of the original pre-sale sticker price.

 

For percentage problems that do not deal with a specific starting number, it is always helpful to plug in 100 for the starting number. Here, we would then have a post-sale price of 90 dollars, and if we calculate the sales tax for the 90-dollar item it would be 90 * 0.09 = $8.10. THis gives us a total cost of 90 + 8.10 = $98.10, or 98.1% of the original 100-dollar price.

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