Question

Charlie runs 2 laps in 8 minutes. How many minutes will 9 laps take him?

Answer 1

36 minutes

Explanation:

We can write a ratio

2 laps 9 laps

------------- = --------------

8 minutes x minutes

Using cross products

2x = 8*9

2x = 72

Divide by 2

2x/2 = 72/2

x = 36 minutes