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03 Apr 2017, 12:44
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55% (hard)

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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 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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13 Jun 2017, 07:54
1
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 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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05 Apr 2017, 10:16
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 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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13 Jun 2017, 15:09
Statement 2 is sufficient because we can use substitution and solve for the remaining variable, correct?
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14 Jun 2017, 09:16
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 06 Jul 2017, 17:19 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 122 Reviews 5-star rated online GMAT quant self study course 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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