Question 632568
A tugboat goes 120 miles upstream in 20 hours. The return trip downstream takes 10 hours. Find the speed of the tug boat without a current, and, find the speed of the current. 
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Upstream DATA:
distance = 120 miles ; time = 20 hrs ; rate = d/t = 120/20 = 6 mph
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Downstream DATA:
distance = 120 miles ; time = 10 hrs ; rate = d/t = 120/10 = 12 mph
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Equations:
b + c = 12 mph
b - c = 6 mph
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Add and solve for "b":
2b = 18 mph
boat speed = 9 mph
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Solve for "c":
b + c = 12 mph
9 + c = 12
current speed = 3 mph
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Cheers,
Stan H.
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