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 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. 

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?

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 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 travel 240 km downstream in 3 hours and the time is taken by the boat to travel the same distance in upstream in 6 hours. Find the speed of stream (in kmph).

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?