the hiker catches up

[sanju09]

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 continue to walk at her constant rate. How many minutes must the cyclist wait until the hiker catches up?
A. 30
B. 25
C. 20
D. 15
E. 10


OA [spoiler]unwillingly C [/spoiler]

[moutar]

In the 5 minutes the hiker will have walked 4*(5/60) = 1/3 mile
The cyclist will have walked 20*(5/60) = 5/3 mile

Therefore the hiker needs to catch up 4/3 miles.

Walking at 4 miles per hour: time = dist/speed = (4/3)/4 = 1/3 h = 20mins

C