Question

A motorboat takes 5 hours to travel 200 miles going upstream. The return trip takes 4 hours going downstream. What is the rate of the boat in still water and what is the rate of the current?

Answer 1

rate of motorboat: b

rate of current: c

So the rate the boat travels upstream is $b - c$, and the rate it travels downstream is $b + c$

Explanation:

d = rt

200 = (b - c)\cdot 5

200 = (b + c)\cdot 4

b - c = 40

b + c = 50

Adding these equations, we get:

2b = 90

b = 45

So

c = 50 - 45 = 5

Therefore the rate of the boat is 45kph, and the rate of the current is 5kph

Hope this helps :)