Aboat traveled 240 miles downstream and back. the trip downstream took 10 hours. the trip back took 30 hours. what is the speed of the boat in stillwater? what is the speed of the current?

A boat traveled 120 miles downstream and back.
The trip downstream took 6 hours.
The trip back took 15 hours.
Find the speed of the boat in still water and the speed of the current.
:
Let s = speed in still water
Let c = speed of the current
then
(s+c) = effective speed downstream
and
(s-c + effective speed upstream
:
Write a distance equation for each trip; dist = time * effective speed
6(s+c) = 120

15(s-c) = 120
Simplify both these equations, divide the 1st by 6; divide the 2nd by 15, results:
s + c = 20
s - c = 8
adding these equations eliminate c, find s
2s = 28
s = 14 mph speed in still water
then
s + c = 20
14 + c = 20
c = 20 - 14
c = 6 mph is the current