Question

Marcie can swim 20 laps in an hour. How many hours will it take her to swim 100 laps

Answer 1

5 hours

Explanation:

It takes Marcie 1 hour to swim 20 laps so to swim 100 laps divide by 20. 100/20=5

Answer 2

5 hours

Explanation:

We can write a ratio

20 laps 100 laps

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

1 hour x hours

Using cross products

20x = 100

Divide by 20

20x/20 = 100/20

x = 5 hours