Question

A boat travel 40 km upstream in a river in the same period of time as it takes to travel 50 km downstream. if the rate of stream be 5km/hr, find the speed of boat in still water.

Answer 1

let its speed in still water is v andit take t time so
40/t=v-5(upstream)
50/t=v+5(downstream)
by eliminating t by dividing these eq you get v=45