Question

If a man goes upstream 10km and comes down taking total time 55min. If the speed of stream is 2 km/hr. Then find the speed of man in still water?

Answer 1

let speed of motor boat = x

downstream speed = x + 2

upstream speed = x - 2

so,

10/(x + 2)+10/(x - 2) = 55/60

55x^2-1200x-220

x=22