[" A swimmer crosses a flowing stream of width "omega" to and from in time "t_(1)" .The time taken to cover the same "],[" distance up and down the stream is "t_(2)" .If "t_(3)" is the time the swimmer would take to swim a distance "2 omega" in "],[" still water,then "]

A swimmer crosses a flowing stream of width omega to and fro in time t_(1) . The time taken to cover the same distance up and down the stream is t_(2) . If t_(3) is the time the swimmer would take to swim a distance 2omega in still water, then

A swimmer crosses a flowing stream of width d' to and fro in time t_(1) . The time taken to cover the same distance up and down the stream is t_(2) , If t_(3) is the time the swimmer would take to swim a distance 2d in still water, then

A swimmer crosses a flowing stream of width d to and fro normal to the flow of the river at time t_(1) . The time taken to cover the same distance up and down the stream is t_(2) . If t_(3) is the time the swimmer would take to swim a distance 2d in still water, then relation between t_(1),t_(2) & t_(3) .

A boat goes 6 km in an hour in still water. It takes thrice as much time in covering the same distance against the stream. What is the speed of the stream?