Question

A boat covers a certain distance downstream in 5 hours, but takes 7 hours to return upstream to the starting point. If the speed of the stream be 5km/hr, find the speed of the boat in still water?

Answer 1

Step-by-step explanation:

let the speed of the boat in still water = xkm/hr

speed in downstream = (x+5)km/hr

speed in upstream = (x-5)km/hr

ATQ,

5(x+5) = 7(x-5)

or, 5x + 25 = 7x - 35

or, 5x - 7x = -35-25

or, -2x = - 60

or, x = 30

Speed of the boat in still water = 30km/hr