GMAT Math : Calculating percents

Study concepts, example questions & explanations for GMAT Math

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Example Questions

Example Question #41 :Percents

A company withemployees is planning to hireadditional employees at the beginning of the next fiscal year. Currently, onlyof the company's employees have a college degree. How many of the additional employees to be hired should have a college degree in order to double the percentage of employees with college degrees?

Possible Answers:

Correct answer:

Explanation:

Currently,of the employees have a college degree; that isout of theemployees. Letbe the number of additional employees who have a college degree:

All of the additional employees to be hired should have a college degree in order to double the percentage of employees with a college degree.

Example Question #42 :Percents

Dmitri bought a new bicycle, which was on sale. If the bike wasoff and he paidfor it, (including asales tax) how much was the bike originally without sales tax?

Possible Answers:

Correct answer:

Explanation:

To begin with, we want to think about his problem conceptually. If Dmitri received a discount, we know our final answer will be higher than what he paid. Eliminate any choices that are less than.

Next, we want to calculate how much the bike cost Dmitri before sales tax. To do this, we want to have a basic equation in front of us to ensure we are setting this up correctly.

or

The cost is what Dmitri paid, and the price is the listed sale price of the bike. We getfrom knowing that sales tax isand that Dmitri paidof the price, plusfor sales tax. Recall that to change from a percent to a decimal, we just move the decimal point two places to the left.

So, we can rearrange the equation to solve for the sale price of the bike before sales tax...

We can round that to the nearest hundredth to get

So, the sale price of the bike was; however, do not choose that as your answer, because we are not done yet! We still need to find the original price of the bike. To do that, another equation will be helpful.

or

This means that the sale price isof the original price, which is the same as saying it isoff.

We knowfrom above, so simply rearrange the equation, plug in the problem's values, and solve to find our final answer:

Again, we can round to the nearest cent to get our final answer of.

Example Question #43 :Percents

is 40% of. What percent ofis?

Possible Answers:

The correct answer is not among the other responses.

Correct answer:

Explanation:

Ifis 40% of, then.

Cube both sides to get

isof, or equivalently,

isof.

Example Question #44 :Percents

is 36% of. What percent ofis?

Possible Answers:

The correct answer is not given among the other responses.

Correct answer:

The correct answer is not given among the other responses.

Explanation:

is 36% of, so

, or

Square both sides:

isof, or, equivalently,of.

This answer is not among the given choices.

Example Question #45 :Percents

is 40% of.

is what percent of?

Possible Answers:

Correct answer:

Explanation:

is 40% of, so.

Eqivalently,

, and

.

The question can be restated as

is what percent of?

This can be answered as

.

Example Question #46 :Percents

is 20 % of.

is what percent of?

Possible Answers:

Correct answer:

Explanation:

is 20% of, so.

The question can be rewritten as

is what percent of?

The answer is found as follows:

# 47例问题:Percents

is 75% of.

is what percent of?

Possible Answers:

Correct answer:

Explanation:

is 75% of, so

and

The question can be rewritten as

is what percent of?

The answer is found as follows:

.

Example Question #48 :Percents

To the nearest whole number, what percent of 5 is 40?

Possible Answers:

Correct answer:

Explanation:

To calculate percent, we need to take one number and divide it by the other. We need to plan out the order carefully, though, because doing the division backwards will yield a trap answer.

We need to find what percent of 5 40 is. It needs to be greater than 100%, because 40 is larger than five. This clues us in that 40 needs to be in our numerator. Perform the following to solve:

Don't stop just yet though, because to convert from decimals to percents we need to multiply by 100. This makes our final answer 800%. So, we can say the 40 is 800% of 5.

Example Question #49 :Percents

To the nearest whole percent, what percent of 108 is 69?

Possible Answers:

Correct answer:

Explanation:

To find percents, simply divide the part by the whole. In this case, we are asked to find what percent 69 is of 108. Take 69 over 108 to find the answer.

Multiply by 100 and round to get our final answer

So, the answer is 64%.

Example Question #50 :Percents

After receiving a% discount on an item, Paola saved. What was the original price?

Possible Answers:

Correct answer:

Explanation:

We can set up an equation to solve this problem whererepresents the orignal price:

That is,% of a number equals theshe saved. Now we just have to solve for:

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