Two ghats are located on a river bank. Leaving one of the ghats for the other downstream, a motorboat returns to the first ghat upstream and it takes 2 hours 40 minutes less time in downstream than upstream. The speed of motorboat in still water is 22.5 km/hr while the speed of river is 9 km/hr. Then find distance between these two ghats?

 Solution : 

D         :        U

22.5+9       22.5-9

31.5     :      13.5 

7          :        3  (speed)

3          :        7(Time)

          4---2h40min

3 = 2hr 

So D=Speed *Time = 31.5 * 2 = 63 Km Ans