Quote:
A hiker walking at a constant rate of 4 miles per hour is passed by a cyclist traveling in the same direction along the same path at a constant rate of 20 miles per hour. The cyclist stops to wait for the hiker 5 minutes after passing her, while the hiker continues to walk at her constant rate. How many minutes must the cyclist wait until the hiker catches up?
Speed of the cyclist = 20 miles per hour
Distance travelled by cyclist in 5 minutes = 20 * 5/60 = 5/3 mile
Speed of the hiker = 4miles per hour
Distance travelled by hiker in 5 minutes = 4* 5/60 = 1/3 mile
Distance between cyclist and hiker after 5 minutes = 5/3 - 1/3 = 4/3 mile
Time taken by hiker to cover this distance = (4/3)/4 = 1/3 hour = 20 min
IMO C