SOLUTION: A boat can go 22km downstream in 2 hours. The return trip takes 6 hours. What would be the speed of the boat if there were no current? What is the rate of the current?
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Question 90376: A boat can go 22km downstream in 2 hours. The return trip takes 6 hours. What would be the speed of the boat if there were no current? What is the rate of the current? Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! A boat can go 22km downstream in 2 hours. The return trip takes 6 hours. What would be the speed of the boat if there were no current? What is the rate of the current?
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Let x = speed of the boat in still water
Let y = speed of the current
:
Speed up-stream = (x-y)
Speed down-stream = (x+y)
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Write two distance equations: Dist = time * speed
:
2(x + y) = 22
6(x - y) = 22
:
2x + 2y = 22
6x - 6y = 22
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Multiply the 1st equation by 3 and add to the 2nd equation:
6x + 6y = 66
6x - 6y = 22
-------------- adding eliminates y
12x = 88
x = 88/12
x = 7 mph boat speed in still water
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Find y using 6x - 6y = 22
6(7)- 6y = 22
44 - 6y = 22
-6y = 22 - 44
y = -22/-6
y = +3 mph is the current
:
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Check solutions using 2(x + y) = 22
2(7 + 3) = 22
2(11) = 22
:
Did this make sense to you? Any questions?
