Jeff takes 20 minutes to jog around the race course one time, and 25 minutes to jog around a second time. What is his average speed in miles per hour for the whole jog if the course is 3 miles long?

A. 6

B. 8

C. 10

D. 12

E. 14

Distance = rate*time

distance/time = rate

The race course is 3 miles around and Jeff does it twice, so the distance he goes = 2*3 miles = 6 miles.

He takes 20 minutes to go around once and 25 minutes to go around the second time, so the total time = 20 min + 25 min = 45 min.

His speed is miles per hour, not miles per minute, so convert 45 minutes to a hours:

45 min/60 min = 0.75 hours distance/time = rate = 6 miles/0.75 hours = 8 mph

Distant = rate time so the answer is B 8