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Difficulty:   55% (hard)

Question Stats: 68% (02:12) correct 32% (01:49) wrong based on 112 sessions

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If the total price for n copies of a book is $31.50, what is the price per copy of the book? (1) If twice as many copies were bought for the same total price, the price per copy would be$1.75.
(2) If 4 fewer copies were bought for the same total price, the price per copy would be $2.80 greater. _________________ Intern  S Joined: 20 Jul 2016 Posts: 25 GMAT 1: 660 Q48 V33 Re: If the total price for n copies of a book is$31.50, what is the price  [#permalink]

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If the total price for n copies of a book is $31.50, what is the price per copy of the book? (1) If twice as many copies were bought for the same total price, the price per copy would be$1.75.
(2) If 4 fewer copies were bought for the same total price, the price per copy would be $2.80 greater. The Cost of per copy =31.50/n 1.31.50/2n=1.75 therefore we can easility find n. 2.31.50/(n-4)=2.80 , Therefore n can be found easily. D is the correct answer because we can find the answer from both A and B independently. Hi, Actually the equation you have written for the second statement is wrong. S2 says that price per copy would increase by$2.8 but your equation means price per copy becomes $2.8. So the correct equation is as follows Initial price per copy = 31.5/n New price per copy = 31.5/(n-4) = 31.5/n + 2.8 _________________ Regards, Nitish +1 kudos if you found this post useful! Director  P Joined: 04 Sep 2015 Posts: 662 Location: India WE: Information Technology (Computer Software) Re: If the total price for n copies of a book is$31.50, what is the price  [#permalink]

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If the total price for n copies of a book is $31.50, what is the price per copy of the book? (1) If twice as many copies were bought for the same total price, the price per copy would be$1.75.
(2) If 4 fewer copies were bought for the same total price, the price per copy would be $2.80 greater. The Cost of per copy =31.50/n 1.31.50/2n=1.75 therefore we can easility find n. 2.31.50/(n-4)=2.80 , Therefore n can be found easily. D is the correct answer because we can find the answer from both A and B independently. Current Student S Joined: 30 May 2017 Posts: 66 Concentration: Finance, General Management GMAT 1: 690 Q47 V38 GPA: 3.23 Re: If the total price for n copies of a book is$31.50, what is the price  [#permalink]

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Statement 2 is sufficient because we can use substitution and solve for the remaining variable, correct?
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nitred wrote:
Smokeybear00 wrote:
Statement 2 is sufficient because we can use substitution and solve for the remaining variable, correct?

Hi,

Not sure what you mean by substitution here.
You will actually get a quadratic equation here. With values of n=9 and n=-5, since n cannot be negative, thus n=9. Hence sufficient.

Hope it helps.

I mean since we now know $$p=\frac{31.50}{n-4}-2.80$$ we can use that in the original equation in place of P, thus solving for n
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Re: If the total price for n copies of a book is $31.50, what is the price [#permalink] Show Tags SajjadAhmad wrote: If the total price for n copies of a book is$31.50, what is the price per copy of the book?

(1) If twice as many copies were bought for the same total price, the price per copy would be $1.75. (2) If 4 fewer copies were bought for the same total price, the price per copy would be$2.80 greater.

We need to determine 31.5/n.

Statement One Alone:

If twice as many copies were bought for the same total price, the price per copy would be $1.75. We can create the following equation: (2n)(1.75) = 31.50 2n = 18 9 = n Thus, 31.5/9 =$3.50. Statement one alone is sufficient to answer the question.

Statement Two Alone:

If 4 fewer copies were bought for the same total price, the price per copy would be $2.80 greater. We can create the following equation: 31.50/(n - 4) = 31.50/n + 2.80 We see that we have enough information to determine n and thus enough information to determine the price per copy. Statement two alone is sufficient to answer the question. Answer: D _________________ Jeffrey Miller Head of GMAT Instruction Jeff@TargetTestPrep.com See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews If you find one of my posts helpful, please take a moment to click on the "Kudos" button. Re: If the total price for n copies of a book is$31.50, what is the price   [#permalink] 06 Jul 2017, 17:19
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