A man rows 12 km in 5 hours against the stream and the speed of current being 4 kmph, What time will be taken by him to row 15 km with the stream? 

A boat rows downstream covers a distance of 20 km in 2 hrs while it covers the same distance upstream in 5 hrs. Then speed of the boat in still water is : 

The speed of the current is 5 km / hour. A motorboat goes 10 km upstream and back again to the starting point in 50 minutes. The speed (in km / hour) of the motorboat in still water is: 

A man can row at a speed of km/hr in still water. If he takes 2 times as long to row a distance upstream as to row the same distance downstream, then the speed of stream (in km/hr) is : 

A motorboat covers a certain distance downstream in a river in 3 hours. It covers the same distance upstream in 3 and half an hour. If the speed of the water is 1.5 km / h, then the speed of the boat in still water is: 

A man swims downstream distance of 15 km in 1 hour. If the speed of the current is 5 km/ hr, the time taken by the man to swim the same distance upstream is : 

A boat covers 24 km upstream and 36 km downstream in 6 hours, while it covers 36 km upstream and 24 km downstream in hours. The speed of the current is: 

The speed of a boat downstream is 15 km/hr. and the speed of current is 3 km/hr. Find the total time taken by the boat to cover 15 km upstream and 15 km downstream.