Question

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

1. What is the cost per book?
2. At this rate, how many books can you buy for 21$

Answer 1

the cost per book is 3$. you can buy 7 books for 21$.

Explanation:

15 divided by 5 is 3, so they cost 3 each. 21 divided by 3 is 7.