If the total price for \(n\) copies of a book is $31.50,

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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.

[spoiler]OA=D[/spoiler]

Source: Princeton Review
Source: — Data Sufficiency |

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by Jay@ManhattanReview » Tue Dec 03, 2019 11:13 pm
VJesus12 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.

[spoiler]OA=D[/spoiler]

Source: Princeton Review
Let's take each statement one by one.

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

Price of 2n copies = 2n*1.75 = 31.5

=> 3.5n = 31.50 => n = 9. Sufficient.

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

31.50/(n - 4) = 31.50/n + 2.80

=> n = 9. Sufficient.

The correct answer: D

Hope this helps!

-Jay
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