Question

A man can row upstream at 8km/ph and downstream at 13km/ph. The speed of the stream is ?

Answer 1

Let the speed of the stream is X and the speed of the boat in still water is Y,

For upstream net speed = Y-X = 8............eq1

For downstream , net speed = Y+X = 13.............eq2

Subtracting eq1 from eq2, we get

2X = 5

=> X = 2.5

Hence the speed of stream is 2.5 kmph.

Answer 2

let speed of man v

speed of stream x

then , v+x= 13

and v-x= 8

adding both equations,

2v=21

v=10.5 km/h

x=13-10.5

x=2.5 km/h

speed of stream is 2.5 k/h