Question
The speed of current is 10 km/h. What will be the
respective downstream speed and upstream speed of a boy rowing a boat, if one sixth of the distance covered going downstream in a certain time is equal to the distance covered going upstream in the same time?Solution
Let the speed of boy in still water be X km/h. And the speed of current = 10 km/h Downstream speed = (X + 10) km/h Upstream speed = (X – 10) km/h Let time be ‘t’ hours. ⇒ [(X + 10) t]/6 = (X – 10) t ⇒ X + 10 = 6X – 60 ⇒ X = 14 km/h Downstream speed = 14 + 10 = 24 km/h Upstream speed = 14 – 10 = 4 km/h
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