Question 474664
A motorboat travels 268 km in 4 hours going upstream.
Rate = distance/time = 268/4 = 67 km/hr
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It travels 420 km going downstream in the same amount of time.
Rate = distance/time = 420/4 = 104 km/hr

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What is the rate of the boat in still water and what is the rate of the current?
Equations:
Upstream: b-c = 67 km/hr
Downstrm: b+c = 104 km/hr
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Add and solve for "b":
2b = 171 km/hr
b = 85.5 km/hr (speed of the boat in still water)
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Solve for "c":
b+c = 104
85.5 + c = 104
c = 18.5 km/hr (speed of the current)

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Cheers,
Stan H.
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