Question 768528
A man can row a boat 4 miles per hour in still water. If he can row downstream three times as fast as he can row upstream, find the rate of the current.

let speed of current = y

Upstream speed = (4-y)

Down stream speed = (4+y)

(4+y) = 3(4-y)

4+y = 12-3y

4y=12-4

4y=8
y=2

speed of current = 2 mph