Boats and stream

Question

A boat covers 12 km in 30 mintues in the direction of water . If the speed of boat in still water is 1/4 of the speed of boat in direction of water then find how much distance boat covers in 20 mintue in still water.

Answer 1

First, find the speed of the boat in the direction of water:

Speed = distance/time = 12 km/0.5 hours = 24 km/hr

Find speed in still water:

0.25*24 = 6 km/hr

Distance covered in still water in 20 minutes: 6 km/hr*1/3 hr = 2 km