Question

Ritu can row downstream 20 km in 2 hours, and upstream 4 km in 2 hours. Find her speed of rowing in still water and the speed of the current.

Answer 1

Let the speed of rowing in still water be x km/hr and the speed of the current be y km/hr

Speed upstream

Speed downstream

Now,

Time taken to cover km down stream =

Time taken to cover km upstream =

But, time taken to cover km downstream in

Time taken to cover km upstream in 2 hours

...(i)

By solving these equation (i) and (ii) we get

Substitute in equation (i)we get

Hence, the speed of rowing in still water is,

The speed of current is .