Question

A man can row 7.5 kmph in still water.if in a river running at 1.5 km/hr an hour,it takes him 50 minutes to row to a place and back,how far off is the place?

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Answer 1

Let the distance be d km.

Because, Speed of the man in still water = 7.5km/h

And speed of the river = 1.5 km/h

Therefore, Speed of the man downstream = 7.5 + 1.5 = 9 km/h

Speed of the man upstream = 7.5 - 1.5 = 6 km/h

According to the question, d/9+d/6=50/60 (in terms of seconds)

=> (4d+6d)36=50/60

=> 10d/36=50/60

=> d=(50×36)/(10×60)

=3km

Hope it helps.

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