Question

At a used book sale, 5 books cost $15.

What is the cost per book?
Type your answer here...
A
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At this rate, how many books can you buy for $21?
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A

Answer 1

The first question is simple. It's $3 for 1 book. The second question is 7.

Explanation:

15/5 = 3

15/5 = 21/x

15x = 105

7

Answer 2

Every book would be $3 so you could buy 7 books for $21