A boat travels 36 miles in 4 hours upstream In the same amou

A boat travels 36 miles in 4 hours upstream. In the same amount of time the boat can travel 48 miles downstream. Find the rate of the current and the rate of the boat in still water

D=RT
36=R*4
R=36/4
R=9 MPH. IS THE SPEED UPSTREAM.
48=R*4
R=48/4
R=12 MPH. IS THE SPEED DOWNSTREAM.
(12-9)/2=3/2=1.5 MPH. IS THE CURRENT SPEED.
PROOF:
12-1.5=10.5 MPH. IS THE SPEED OF THE BOAT
9+1.5=10.5 MPH.