A boatman rows his boat 35 km upstream and 55 km downstream in 12 hours and he can row 30 km upstream and 44 km downstream in 10 hours. Find the speed of the stream and that of the boat in still water.

Explanation

let speed of boat in still water`= u`Km/hr

let speed of boat in stream `= v` Km/hr

upstream `= u-v`

downstream `=u+v`

forming equations according to question

`35/(u-v) + 55/(u+v) = 12` eqn(1)

`30/(u-v) + 44/(u+v) = 10` eqn(2)

let `u-v= a & u+v=b`

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