Question

a motor boat whose speed in still water is 5 km per hour takes 1 hour more to go 12 km upstream then to return downstream to the same spot find the speed of the stream

Answer 1

the speed of stream is 7km/hr

Answer 2

Let speed of stream = x km/h
Speed of boat in still water = 5km/h
Speed of boat in upstream = (5 - x)km/h
Speed in downstream = (5+x)km/h
Distance = 12km
let time to go downstream = y hours
Time to go upstream = (y+1)hours
Speed = Distance/time
5-x = 12/(y+1)
(5-x)(y+1)=12
5y + 5 -xy-x = 12
5y-xy-x=7. eq.1

5+x = 12/y
(5+x)(y) = 12
5y + xy =12. eq.2
Solve both equations and u will get the answer