A canoeist paddled 4 hours with a 6kmh current to reach a ca

A canoeist paddled 4 hours with a 6=km/h current to reach a campsite. The return trip against the same current took 10 hours. Find the speed of the canoe in still water.

Solution

let the rate of paddling on the trip there = x+6km
Let the rate returning =x-6km
the distance is the same both ways,
using rate*time=distance, we have two equations:
(x+6)*4=d
(x-6)*10=d
Set them equal to one another,
(x+6)*4=(x-6)*10
4x+24=10x-60
subtract 4x and add 60 to both sides:
84=6x
divide by 6
14=x
the canoe traveled 14mph in still water.