please help me to solve this problem
A swimmer going downstream takes 1hour,20minutes to travel a certain distance. It takes the swimmer 4hours to make the return trip against the current. If the river flows at the rate of 1.5mph. Find the rate of the swimmer in still water and the distance traveled one way.
Let the distance be D and the speed in still water be v. Here is what you know:
D = speed * time = 4*(v-1.5)
D = (4/3)*(v+1.5)
Solve for both unknowns.
4(v-1.5) = (4/3)(v+1.5)
(8/3)v = 6 + 2 = 8
v = 3 mph
D = (4/3)(4.5) = (4/3)(9/2) = 6 miles