SOLUTION: A boat can travel 34 mph in still water. If the boat can travel 100 miles with the current in the same time it can travel 80 miles against the current, find the rate of the current

Question 1051751: A boat can travel 34 mph in still water. If the boat can travel 100 miles with the current in the same time it can travel 80 miles against the current, find the rate of the current r in miles per hour. (Enter an exact number as an integer, fraction, or decimal.)
Found 2 solutions by jorel555, stanbon:
Answer by jorel555(1290) (Show Source): You can put this solution on YOUR website!
Let r be the rate of the current. Then:
100/(34+r)=80/(34-r)
100(34-r)=80(34+r)
3400-100r=2720+80r
180r=680
r=3.78 mph as the rate of the current in mph. ☺☺☺☺
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A boat can travel 34 mph in still water. If the boat can travel 100 miles with the current in the same time it can travel 80 miles against the current, find the rate of the current r in miles per hour. (Enter an exact number as an integer, fraction, or decimal.)
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downstream DATA:
dist = 100 miles ; rate = 34+c ; time = 100/(34+c) hrs
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upstream DATA:
dist = 80 miles ; rate = 34-c ; time = 80/(34-c) hrs
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Equation::
100/(34+c) = 80/(34-c)
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3400 - 100c = 2720 + 80c
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680 = 180c
c = 3.78 mph (speed of the current)
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Cheers,
Stan H.
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