SOLUTION: Alvin paddled for 2hours with a 8-km/h to reach a campsite. The return against the same current took 10 hours. What is the speed of the boat in still water.

Algebra ->  Graphs -> SOLUTION: Alvin paddled for 2hours with a 8-km/h to reach a campsite. The return against the same current took 10 hours. What is the speed of the boat in still water.      Log On


   



Question 323351: Alvin paddled for 2hours with a 8-km/h to reach a campsite. The return against the same current took 10 hours. What is the speed of the boat in still water.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Alvin paddled for 2hours with a 8-km/h to reach a campsite.
The return against the same current took 10 hours.
What is the speed of the boat in still water.
:
Let s = boat speed in still water
then
(s+8) = effective speed downstream
and
(s-8) = effective speed upstream
:
Write a distance equation, (distance both ways is the same) dist = time * speed:
:
Upstream dist = downstream dist
10(s-8) = 2(s+8)
10s - 80 = 2s + 16
10s - 2s = 16 + 80
8s = 96
s = 96%2F8
s = 12 km/hr, boat speed in still water
:
:
Check solution, find the dist of both trips, should be equal:
10(12-8) = 40
2(12+8) = 40; confirms our solution