A river 2 km wide is flowing at the rate of 2km/hr. A boatman, can row the boat at a speed of 4 km/hr in still water, goes a distance of 2 km upstream and them comes back. The time taken by him to complete his journey is

A river 5 Km wide is flowing at the rate of 2 Km/H. The minimum time taken by a boat to cross the river with a speed 5 Km/H (in still water) is approximately

A river flows at the rate of 3km/hr and a person can row a boat at a speed of 5km/hr in still water.If the difference between the times taken to cross the river by the shortest path and the quickest path be 4 minutes,the width of the river is (in km)