Question

Noreen can walk 1/3 of a mile in 12 minutes what is her average speed in miles per hour. (this is multiple choice)

A. 36 miles per hour
B. 12 miles per hour
C. 1/4 a mile per hour
D. 1 2/3 miles and hour

Answer 1

Step-by-step explanation:

1/3 mile in 12 minutes (=1/5 of an hour).

so, the speed (ratio of distance/time) is

1/3 mile / 12 minutes

the speed in mph is the converted ratio, where the denominator (bottom) is turned into 1 (hour).

what do I need to multiply 12 minutes with to get 1 hour ?

the same to multiply 1/5 with to get 1 : 5

to keep the overall value of the ratio the same I need to multiply both parts (top and bottom) of the fraction with the same value.

therefore,

1/3 / 12 × 5/5 = (1/3 × 5) / (12×5) = 5/3 / 60

so, the speed in mph is

5/3 miles / 60 minutes = 5/3 miles / 1 hour = 5/3 mph = 1 2/3 mph

D is the right answer.