Question

A motorboat take 5 hours to travel 100 km going upstream. The return trip take 2 hours going downstream. what is the rate of the boat in still water? What is the rate of the current?

Answer 1

b= boat speed
r = river speed

d=rt
the rate of the river will either be added or subtracted from the rate of the boat

upstream
100=(b-r)(5)
100=(b+r)(2)

50=b+r
20=b-r

b=20+r
20 + 2r = 50

r=15km/h
b= 35km/h