SOLUTION: The speed of a stream is 4 mph. A boat travels 11 miles upstream in the same time it takes to travel 19 miles downstream. What is the speed of the boat in still​ water?
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Question 1115356: The speed of a stream is 4 mph. A boat travels 11 miles upstream in the same time it takes to travel 19 miles downstream. What is the speed of the boat in still water? Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! The speed of a stream is 4 mph. A boat travels 11 miles upstream in the same time it takes to travel 19 miles downstream. What is the speed of the boat in still water?
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Upstream DATA:
dist = 11 miles ; rate = b-4 mph ; time = d/r = 11/(b-4)
Downstream DATA:
dist = 19 miles ; rate = b+4 mph ; time = d/r = 19/(b+4)
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Equation:
time up = time down
11/(b-4) = 19/(b+4)
11b+44 = 19b - 76
8b = 120
b = 15 mph (speed of the boat in calm water)
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Cheers,
Stan H.
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