Question

Riya can row down stream at 20km in 2 hours and upstream 4km in 2 hours find the speed of rowing in still water and current

Answer 1

To do this, you need to form equations using the information given. There are 2 variables here, the base speed of the rower with no current (x), and the speed of the current (y).  

Firstly, convert the distances and times given into average speeds.  

20km/2 hours = 10km/h  

4km/2 hours = 2km/h

The actual speed = the base speed +- the current, depending on direction.

So 10 = x + y  

2 = x - y

If we subtract these 2 equations to eliminate x, we get:  

8 = 2y  

y = 4km/h