Question

Salman can row downstream 20kmin 2 hours and upstream in 4 km in 2 hours. Find his speed of rowing in still water and the speed of the current.

Answer 1

Let speed of water is x and speed of current is y

So, downstream speed = x + y and upstream speed = x – y

Given, 20 km in downstream in 2 hours, so it becomes 

20/x+y = 2

x + y = 10          ------------------- (i)

Given, 4km in upstream in 2hrs, So it becomes

4/x-y = 2

x-y = 2     ------------------- (ii)

On solving (i) and(ii) we get

x + y + x -y = 10 + 2

2x = 12

x = 6

On submitting x = 6 in (1) we get y = 4.

Speed of rowing in water = 6km/hr

Speed of current = 4km/hr.

Hope this helps!