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: 

A man can swim at the rate of 3 km/hr. in still water. Then, if speed of the stream is 2 km/hr., then in what time he will cover a total distance of 5 km in with the stream and against the stream?

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. 

Speed of a boat in still water is 12 kmph and that of the current is 3 kmph. A man row a boat upstream up to 135 km and return downstream to the starting point. Find the total time taken for the entire journey in hours.

The speed of the motorboat in still water is 45 kmph. If the motorboat travels 80 km along the stream in 1 hour 20 minutes, then the time taken by it to cover the same distance against the stream will be: 

Two boats are traveling with speeds of 36 km/hr and 54 km/hr respectively towards each other. What is the distance (in meters) between the two boats one second before they collide?

A boat takes half time in moving a certain distance downstream than upstream. what is the ratio between the rate in still water and the rate of current? 

A person rows a distance of upstream in and a distance of 13 km downstream in 2 hours. How much time ( in hours) will the person take to row a distance of 90 km in still water?