SOLUTION: A boy can row a boat at a constant rate of 3mi/hr in still water. He rows up-stream for 20 minutes and then rows down-stream, returning to his starting point in another 15 minutes.

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons -> SOLUTION: A boy can row a boat at a constant rate of 3mi/hr in still water. He rows up-stream for 20 minutes and then rows down-stream, returning to his starting point in another 15 minutes.      Log On


   

Question 213173: A boy can row a boat at a constant rate of 3mi/hr in still water. He rows up-stream for 20 minutes and then rows down-stream, returning to his starting point in another 15 minutes. Find the total distance traveled.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
A boy can row a boat at a constant rate of 3mi/hr in still water. He rows up-stream for 20 minutes and then rows down-stream, returning to his starting point in another 15 minutes. Find the total distance traveled.
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Upstream DATA:
time = 1/5 hr ; rate = 3+c ; distance = rt = (1/5)(3+c) miles
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Downstream DATA:
time = 1/4 hr ; rate = 3-c ; distance = rt = (1/4)(3-c) miles
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Equation:
Up distance = Down distance
(1/5)(3+c) = (1/4)(3-c)
Multiply both sides by 20 to get:
4(3+c) = 5(3-c)
12+4c = 15-5c
9c = 3
c = 1/3 mph (speed of the current
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Cheers,
Stan H.