<PRE><B>Question 509344</B>
a motorboat can maintain a constant speed of 16 miles per hour relative to the water. The boat makes a trip upstream to a certain point in 20 minutes the return takes 15 minutes. what is the speed of the current?
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Upstream DATA:
time = 1/3 hr ; rate = 16-c mph ; distance = r*t = (1/3)(16-c) miles
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Downstream DATA:
time = 1/4 hr ; rate = 16+c mph ; distance = r*t = (1/4)(16+c)
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Equation:
distance = distance
(1/3)(16-c) = (1/4(16+c)
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4(16-c) = 3(16+c)
64-c = 48+c
16 = 2c 
current = 8 mph
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Cheers,
Stan H.
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