Question

A man can row 18kmhr in still water and finds that it takes him twice as long as to row up to row down the river.find the rate of stream ?

Answer 1

Explanation:

Let say distance = D km

Speed of Stream = S km/Hr

Upstream speed (row up) = 18 - S km/Hr

Upstream Time = D/(18-S)

Downstream speed (row up) = 18 + S km/Hr

Downstream Time = D/(18+S)

Upstream Time = 3 * Downstream Time

=> D/(18-S) = 3 * D/(18+S)

=> 18 + S = 54 - 3S

=> 4S = 36

=> S = 9

the rate of stream = 9 km/Hr