Question

A motorboat takes 3 hours to travel 108km going upstream. The return trip takes 2 hours going downstream. What is the rate of the boat in still water and what is the rate of the current?

Answer 1

vb + vs = 108/3  = 36

vb - vs = 108/2   =54

2vb    = 90
vb      = 45 . . . motorboat speed

rate of current  = 45 - 36    = 9

Hope this helps