In still water a boy rows 5 miles an hour. Wait the aid of current he can make a 21 miles trip in 3 hours. How fast is the current?

In still water a boy rows 5 miles an hour. Wait the aid of current he can make a 21 miles trip in 3 hours. How fast is the current?

A 2 miles

B 4 miles

C 6 miles

D 3 miles

Solution

Correct Answer: Option C