# motion problem

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A man rowed 30km downstream. it took him 2hrs more time in going back than in going downstream. if the current is 2kph, what is his speed in still water?

(with solution pls... tnx)

• motion problem -

since time = distance/speed, if his speed is s, then

30/(s-2) = 2 + 30/(s+2)
s = 8

check:
downstream: 30/10 = 3
upstream: 30/6 = 5

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