Fred paddled for 3 hours with a 5 kmhr current to reach a ca

Fred paddled for 3 hours with a 5 km/hr current to reach a campsite. The return trip against the same current took 10 hr. Find the speed of Freds canoe in still water.

D=RT
D=(X+5)*3
D=(X-5)*10
3(X+5)=10(X-5)
3X+15=10X-50
3X-10X=-50-15
-7X=-65
X=-65/-7
X=9.29 KM/HR. IS THE SPEED OF THE CANOE.