Jeff takes 20 minutes to job 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 wh

Question

Jeff takes 20 minutes to job 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

 

How would I solve this?

Answer 1

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