Question

Olivia takes twelve laps on a long track in fifteen minutes. how much time will it take her to skate thirty laps ?

A.20.5 minutes
B.12 minutes
C.37.5 minutes
D. 18.5 minutes

Answer 1

C. 37.5 minutes

Explanation:

You can set up a proportion to help you figure this out.

12/15=30/x (in this proportion, the number of laps are both on the numerator and the time it takes her is on the denomiator.)

Now, just cross multiply and your equations should be: 12·x=15·30, which equals to 12x=450.

Divide 12 on both sides and x=37.5

Answer 2

C. 37.5 minutes

Explanation:

Step 1: Olivia completes 12 laps in 15 minutes.

Find the unit rate. It is nothing time taken to complete 1 lap.

= 15/12

= 1.25 minutes

Step 2: Now find the time taken to complete 30 laps.

Multiply 30 by 1.25

= 30 *1.25

= 37.5 minutes.

Thank you. :)