Bunuel wrote:

A man travels a distance of 20 miles at 60 miles per hour and then returns over the same route at 40 miles per hour. What is his average rate for the round trip in miles per hour?

(A) 50

(B) 48

(C) 47

(D) 46

(E) 45

We can use the following formula:

average = (total distance)/(total time)

Average = 40/(20/60 + 20/40)

Average = 40/(1/3 + 1/2)

Average = 40/(2/6 + 3/6)

Average = 40/(5/6) = 240/5 = 48

Answer: B

_________________

Scott Woodbury-Stewart

Founder and CEO

GMAT Quant Self-Study Course

500+ lessons 3000+ practice problems 800+ HD solutions