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For a certain city's library, the average cost of purchasing each new

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KarishmaB

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22 Jul 2025, 01:11

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Rohanx9

KarishmaB

I'm finding this question to be flawed. I don't believe the average cost per book of $28 is reliable enough to use as a constant in statement 1.

We aren't given the fact that the small sample size of n = 50 books per month (or by extrapolation n = 600 for the year) is statistically significant enough to be similar to the population size of the books, and hence the average price of the books.

To me, a clearer way of asking the question is simple saying the price of a book is $28. Including the word "average" can lead to subjectivity in interpretation, as everyone's confidence that the price of $28 represents the sample mean is subjective given the lack of information.

This could be a trap in a question, but in this case it wasn't.

I am given that the average cost of purchasing each new book is $28. So if I am talking about a bunch of books, their average cost of purchase must be $28 per book. Otherwise, this data point makes no sense. Even if you assume that $28 is not applicable to every book, you can certainly assume the cost per book as $28 for the 600 books. GMAT expects you to.

ManishaPrepMinds

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23 Jul 2025, 01:48

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We are given:

Book cost = $28
Library receives $15,000 annually, and an additional $2,000 if more than 5,000 items are checked out
Question: Did the library receive the $2,000 bonus last year?

Statement 1 Analysis:

Books purchased per year = 50 × 12 = 600
Total Cost = 600 × 28 = $16,800
But city gives only $15,000 unless bonus is earned.
So if the library spent $16,800 and had enough funds from the city, it must have received the bonus:

Statement (1) ALONE sufficient.

Statement 2 Analysis:

The lowest number of items checked out in one month was 459.
That means every month, at least 459 items were checked out.
Minimum total checkouts = 459 × 12 = 5,508 items
So total items checked out > 5,000
→Bonus was received

Statement (2) ALONE sufficient

Answer: (D)

AbdurRakib

For a certain city's library, the average cost of purchasing each new book is $28. The library receives $15,000 from the city each year,the library also receives a bonus of $2,000 if the total number of items checked out over the course of the year exceeds 5,000.Did the library receive the bonus last year ?

(1) The library purchased an average of 50 new books each month last year and received enough money from the city to cover this cost.

(2) The lowest number of items checked out in one month was 459 .