A man travel in his yacht downstream at d knots and returns the same distance upstream at u knots. What is his average rate for the round trip if the length of stream is 1:
Imran speed of rowing in still water is 9 km/h and he finds that it takes him twice as long to row up as to row down the river. Find the speed of water in the river.
Speed of water in certain river is 2 km/h and it takes a boat thrice as long to row up as to row down the river. Find the speed of the boat in still water.
