<PRE><B>Question 931721</B>
x = speed of current
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s = d/t
t = d/s
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downstream:
t = 120/(20 + x)
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upstream:
t = 70/(20 - x)
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equate times:
120/(20 + x) = 70/(20 - x)
120(20 - x) = 70(20 + x)
2400 - 120x = 1400 + 70x
190x = 1000
x = 1000/190
x = 5.263157894740000
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answer:
x = speed of current = 5.26 mph
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