GRE Math : Arithmetic

Study concepts, example questions & explanations for GRE Math

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Example Questions

Example Question #1 : Profit Margin

A grade school pays Mr. Day a salary of $24,585 per school year.  Each school year contains 165 days.  Suppose Mr. Day is sick for a week (5 work days) and the school doesn't have to pay him for those days.  Instead, they must pay a substitute teacher to teach his classes.  They pay the substitute $90 per day. Totally, how much does the school save for the week Mr. Day is sick?

Possible Answers:

$59

The answer cannot be determined from the given information.

The school must pay $59 extra for the substitute teacher.

$295

$205

Correct answer:

$295

Explanation:

Divide Mr. Day's salary by 165 to determine how much the school pays him per day: Mr. Day makes $149 per day.  They only have to pay substitute $90 per day, saving them $59 per day. To figure out how my they save totally, multiply by 5 to get how much they save for the week Mr. Day is sick: $295. 

Example Question #53 : Percentage

What percentage of profit is made on a product sold for $20 if its overall production cost was $17.50?

Possible Answers:

25%

15.252%

87.5%

46.67%

14.29%

Correct answer:

14.29%

Explanation:

To find the profit percentage, you must first determine the amount of profit made on this transaction.  If the sale price was $20 and the production cost $17.50, then the profit made was: 20 -17.5 = $2.50.  The profit percentage is determined by dividing the amount of profit made by the original price, or 2.5 / 17.5 = (approx.) 0.14286 or 14.29%.

Example Question #1 : Profit Margin

Manufacturer X has a base monthly operating cost of $30,000.  It makes only one product, which costs $5 per piece in addition to the base operational costs for the plant.  These products are each sold for $15 apiece.  How many products must the company sell in order to break even in any given month?

Possible Answers:

3,000

2,000

10,000

1,500

2,500

Correct answer:

3,000

Explanation:

Begin by translating your problem into an equation.  What we want to ascertain is the situation when the profit equals exactly 0.  The profit and loss for a given month can be summarized by the following equation:

(Total product revenue) - (Base operating costs) - (Individual costs for products) = 0

Given our data, we can rewrite this:

15 * x - 30,000 - 5 * x = 0

Combine like terms:

10 * x - 30,000 = 0

Isolate x:

10 * x = 30,000; x = 3,000.

Therefore, the manufacturer must sell at least 3,000 items per month in order to "break even."

Example Question #2 : Profit Margin

A new t-shirt has a total cost of 8 dollars for a given retailer.  Its current price is $15. If the retailer discounts the cost of the shirt by 20%, how many must it sell in order to make the same amount of profit as when it sold 300 of the shirts at the original price?

Possible Answers:

None of the other answers

525

400

395

360

Correct answer:

525

Explanation:

First, we must ascertain the original profit.  Per shirt, the retailer made 15 – 8, or $7.  Selling 300 shirts, it made a profit of $2,100.

The new price, discounted by 20% is equal to 80% of the original price, or 15 * 0.8 = $12.  This yields a profit of $4 per shirt.

To ascertain the number of sales needed to make $2,100 in profit, we must solve the following equation:

4x = 2100; x = 525 shirts

Example Question #54 : Percentage

A laptop computer costs $235 to manufacture. If it is sold for $578, what is the percent of profit made on the item?

Possible Answers:

59.34%

245.96%

53.38%

145.96%

343%

Correct answer:

145.96%

Explanation:

The amount of profit made on the item is 578 – 235 = $343. This is 343/235 or (approximately) 1.4596, which is 145.96% of the original price.

Example Question #3 : Profit Margin

Sally buys a dress that is a 20% discount from the original price. If she sells it at a 10% markup from her purchase price and profits $10 from the sale, what was the original price of the dress?

Possible Answers:

120

20

110

100

125

Correct answer:

125

Explanation:

Set Original = O

and Discount = D

then 

D = (1 – 20%) x O = 0.80 x O

and Profit = $10 so:

10 = ((1 + 10%) x D) – D = 1.1 * D – D = 0.1D

D = 100

and O = D / 0.8 = 125

Example Question #4 : Profit Margin

A shirt costs $12 to manufacture. If the marketing and sales costs are a 75% addition to this manufacturing cost. What is the minimum price necessary for making a 50% profit?

Possible Answers:

$21

$16.5

$18

$31.5

$10.5

Correct answer:

$31.5

Explanation:

Based on the prompt, we know that the additional marketing and sales costs are 12 * 0.75 = 9; therefore, the total cost for purchase and sale is 12 + 9 = $21. To make a 50% profit, we must make 21 * 0.5, or $10.5, on the sale; thus the shirt must be sold for 21 + 10.5, or $31.5.

Example Question #55 : Percentage

A factory has fixed costs of $25,000 per month. It manufactures widgets at a total manufacturing cost of $45 per widget. They are sold at $60. How many widgets must be sold in any given month in order to break even?

Possible Answers:

1666

555

1753

556

1667

Correct answer:

1667

Explanation:

Let's first represent the total costs per month:

C = 25000 + 45n, where n is the number of widgets manufactured.

The profit can be represented as 60n – C or 60n – 25000 – 45n = 15n – 25000. Now, we merely have to solve this for 0 in order to find the "break even" line. 

15n – 25000 = 0 → 15n = 25000 → n = 1666.67.  We must sell a whole number of widgets, so it must be 1667.

Example Question #1 : Profit Margin

A boy with a lemonade stand sells cups of lemonade for a quarter each. He has bought  worth of supplies and is able to make  of lemonade with the supplies. If he has to pay a business tax of  for each cup he sells, how many cups will he have to sell in order to break even?

Possible Answers:

Correct answer:

Explanation:

To solve this problem we must first find out how cups he must sell without tax to break even. If each cup of lemonade costs a quarter and he has spent $20 on supplies, that means in order to make back the original $20 he spent, he must sell .  Due to this 4% business tax, he must sell 4% more in order to break even. To find that amount, we simply multiply that 4% by the number of cups he must sell without tax to break even, . He must sell an additional 3.2 cups in order to break even, however it is impossible to sell 0.2 of a cup of lemonade, therefore he must sell a minimum of 84 cups of lemonade in order to break even.

Example Question #1 : How To Find The Percent Of Increase

Harry and Gerry each own equal shares in a gardening company. Their partner, Izzy, owns 40% of the company. What is the percentage increase of the sum of Harry's and Gerry's shares above Izzy's share in the company?

Possible Answers:

100%

150%

50%

33.3%

20%

Correct answer:

50%

Explanation:

This basic percentage problem asks you to determine by what percentage the sum of Harry's and Gerry's share of the company is greater than ("exceeds") Izzy's share. Harry's and Gerry's share's are equal, and the sum is 60% of the company (100% – Izzy's 40% = 60%). 60% is 50% greater than 40% (0.40 * 1.5 = 0.60). Examinees may be tempted to go too far with the problem and mistake their task by finding how much greater Izzy's share is than either Harry's or Gerry's. Be careful to read instructions and translate keywords appropriately.

You may think the answer is 20% (60% – 40%), but this is the difference in terms of total shares in the company, not in terms of Izzy's shares, which is what the question is asking.

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