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Question 1132762: A boat travelled 32 miles downstream and then it travelled back. The trip downstream took 4 hours. The trip back took 8 hours. What is the speed of the boat in still water? What is the speed of the current.
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! A boat travelled 32 miles downstream and then it travelled back.
The trip downstream took 4 hours. The trip back took 8 hours.
What is the speed of the boat in still water?
What is the speed of the current.
:
let s = speed of boat in still water
let c = rate of the current
then, in relation to the earth:
(s+c) = speed downstream
and
(s-c) = speed upstream
:
Write a distance equation for each way
4(s+c) = 32
8(s-c) = 32
Simplify, divide the 1st equation by 4 and the 2nd equation by 8
s + c = 8
s - c = 4
----------addition eliminates c, find s
2s = 12
s = 6 mph is the speed in still water
and
6 + c = 8
c = 2 mph is the rate of the current
:
Check this by finding the travel times with these values
32/(6+2) = 4
32/(6-2) = 8
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