GED Math : Proportions and Percentages

Study concepts, example questions & explanations for GED Math

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Example Questions

Example Question #11 : Proportions And Percentages

Each student at an Asian-studies school is required to take one of three languages - Japanese, Chinese, or Korean. 15% of the students have chosen to take Korean, and three times as many have chosen to take Chinese. No student takes more than one language. What fraction of the students are taking Japanese?

Possible Answers:

Correct answer:

Explanation:

15% of the students are taking Korean, and three times this, or 45%, are taking Chinese. This leaves

of the students taking Japanese. This is

of the students.

Example Question #12 : Proportions And Percentages

Each student at a college preparatory school is required to take one of three languages - French, German, or Russian. One fifth of the students have chosen to take Russian; there are twice as many students who have chosen to take French as there are students who have chosen to take German. No student takes more than one language.

What percent of the students are taking German?

Possible Answers:

Correct answer:

Explanation:

One fifth of the students are taking Russian - this is 

 of the students.

This leaves  taking either French or German.

Let  be the percent taking German. Then  percent are taking French. This means

This is the correct response.

 

Example Question #13 : Proportions And Percentages

Twenty

Refer to the above figure. The portions of the rectangle are of equal size. 

What percent of the figure is white?

Possible Answers:

Correct answer:

Explanation:

Out of the 20 portions of equal size, 6 are white. We find out what percent 6 is of 20 as follows:

Example Question #11 : Proportions And Percentages

One foot on a large map represents 100 miles of real distance. The distance between Harrison and Tyler is 328 miles. To the nearest inch, what is the distance between the two cities on the map?

Possible Answers:

Correct answer:

Explanation:

One foot, or twelve inches, on the map represents 100 miles - a map inch to mile ratio of . If Harrison and Tyler are  inches apart on a map and 328 miles apart in reality, then the map inch to mile ratio is . These ratios must be equal, so we solve for  in the proportion statement:

The cities will be 39 inches apart on the map.

Example Question #15 : Proportions And Percentages

Barry currently pays $580 in rent per month. As a reward for referring some new renters, Barry's landlord will decrease his rent by 20% from January through April, after which it will revert back to the current amount. How much rent will Barry pay from January to December?

Possible Answers:

Correct answer:

Explanation:

20% of $580 is ; for four months, Barry's rent will be 

Barry will pay  for four months and  for the remaining eight, for a total of 

Example Question #11 : Proportions And Percentages

Julie has a gift card with $500 worth of credit on it. She wants to spend it at the store where she works, because she gets a 30% employee discount; also, the sales tax in the location of the store is 7%.

What is the maximum price, before discount and tax, of the merchandise that Julie can buy with the card?

Possible Answers:

Correct answer:

Explanation:

Let  be the price of the merchandise before the discount and the tax is figured in.

Julie gets a 30% discount, so, after discount but before tax, the goods will cost her

.

Including the tax of 7%, she will pay

.

This can be at most $500, so we need to solve for  in the inequality

Since we are looking at a maximum, we should round down to the nearest cent, so Julie can buy at most $667.55 worth of merchandise.

Example Question #11 : Proportions And Percentages

John’s weight decreased from 320 pounds to 280 pounds. By what percent (nearest tenth, if applicable) did his weight decrease?

Possible Answers:

Correct answer:

Explanation:

In a percent of decrease problem, the whole is the amount at the beginning of the time period, which here is 320 pounds. The part is the difference between the final and initial amounts, which here is  pounds. To find what percent 40 is of 320, calculate:

Example Question #18 : Proportions And Percentages

To get on the ballot for Student Council at Cesar Chavez Junior High School, a student must turn in a petition with the signatures of 8% of all of the students. Chavez Junior High School has students from two grades - 311 seventh-grade students and 302 eighth-grade students.

Serena has a petition with the names of 32 seventh-grade students and 16 eight-grade students. Does she have the signatures she needs to get on the ballot, and if not, why not?

Possible Answers:

Serena cannot get on the ballot yet, because she does not have enough signatures overall.

Serena has the signatures she needs to get on the ballot.

Serena cannot get on the ballot yet, because she does not have enough signatures from eight-grade students.

Serena cannot get on the ballot yet, because she has too many signatures from seventh-grade students.

Correct answer:

Serena cannot get on the ballot yet, because she does not have enough signatures overall.

Explanation:

There is only one qualification to get on the ballot - having 8% of the total number of students; this is the only thing we need to test.

Serena has  signatures out of  students overall. This is

of the students, which is not enough to get on the ballot. 

The correct response is that Serena cannot get on the ballot yet, because she does not have enough signatures overall.

 

Example Question #19 : Proportions And Percentages

A salesman for a car dealership earns 15% commission on all sales. What will be his commission for a week if he sells three cars that week - a $35,000 SUV on Tuesday, a $24,000 car on Thursday, and a $40,000 van on Friday?

Possible Answers:

Correct answer:

Explanation:

The total sale price of the cars he sells will be

.

15% of $99,000 is

,

which is the salesman's commission.

Example Question #20 : Proportions And Percentages

A salesperson for a car dealership earns 20% commission on all sales. She has sold one vehicle this week - a $52,000 van on Tuesday, and today is Saturday. She would like to earn a total of $20,000 in commissions by week's end. At the very least, how much in sales must she accomplish today to meet her goal?

Possible Answers:

She has already met her goal.

Correct answer:

Explanation:

First, we find out what the salesperson's total sales must be in order to reach her commissions goal:

She has already made $52,000 in sales, so she must sell at least

 in vehicles.

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