Amotorboat takes 5 hours to travel 200 km 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?

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 $b + c$







Adding these equations, we get:



So


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

Hope this helps :)