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Re: At the start of a certain week, a school library had 100 comic books,
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30 Mar 2023, 09:33
To find the maximum number of comic books issued during the week, we need to maximize the number of comic books that were not returned by Saturday morning. Let x be the number of comic books issued on Tuesday. Then, the number of comic books issued on Wednesday is 2x.
On Tuesday, 25% of the comic books issued were returned, so 75% were not returned. On Wednesday, 12.5% of the comic books issued were returned, so 87.5% were not returned. Therefore, the total number of comic books that were not returned by Saturday morning is:
100 + 0.75x + 0.875(2x) = 100 + 0.75x + 1.75x = 100 + 2.5x
We know that this number is at least 40, so:
100 + 2.5x >= 40
2.5x >= -60
x >= -24
Since x is the number of comic books issued on Tuesday, it must be a positive integer, so we take the smallest possible value of x that satisfies the inequality above, which is x = 24. Then, the number of comic books issued on Wednesday is 2x = 48.
Therefore, the maximum number of comic books issued during the week is 24 + 48 = 72. The correct answer is (C) 72.