Question 571547
it takes bob the boy scout 10 hours to paddle upstream against the current a distance of 15 miles. when he turn around he finds it only takes him 5 hours to 'paddle 22.5 miles with current. how fast is bob's boat going in still water and what is the speed of the current of the river?
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Upstream DATA:
time = 10 hrs ; distance = 15 miles ; rate = d/t = 15/10 = 1.5 mph
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Downstream DATA:
time = 5 hrs ; distance = 22 miles ; rate = d/t = 22/5 = 4.4 mph
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Equations:
upstream: b-c = 1.5 mph
downstream: b+c = 4.4 mph
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Add and solve for "b":
2b = 5.9 mph
b = 2.95 (speed of the boat in still water)
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Solve for "c":
b + c = 4.4
2.95 + c = 4.4
c = 1.45 mph (speed of the current)
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Cheers,
Stan H.
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