Question

Sam can solve 30 multiplication problems in 2 mins. How many can he solve in 20 mins.

Answer 1

To find the answer using unit rates, you do 30 divided by 2 which is 15/1. Then do 15*20 which is 300. So he can do 300 problems in 20 minutes.

Answer 2

To get to 20 minutes from 2 minutes you multiply by 10, do the same to the 30 problems to get 300. The answer is 300 problems in 20 minutes.