A woman drives her snowmobile 240 miles at the rate of r mph. She could have gone the same distance in 2 hours less time if she had increased her speed by 20 mph. Find r .
A) 27 mph
B) 41 mph
C) 44 mph
D) 57 mph
E) 40 mph

Question

Quizplus · Accepted Answer

The equation for time is distance divided by speed. The time taken at speed r is 240/r. The time taken at speed r+20 is 240/(r+20). The difference in time is 2 hours, so 240/r - 240/(r+20) = 2. Solving this equation gives r = 40 mph.

A Woman Drives Her Snowmobile 240 Miles at the Rate