# Boats And Streams

Concept of Boats And Streams
A boat is going downstream if it is moving along the direction of the stream. Here the net speed of the boat is called downstream speed. A boat is going upstream if it is moving in the direction opposite to the direction of the stream.

Points to Remember
1) If the speed of the boat is A km/hr and the speed of the stream is B km/hr,
The speed of the boat in the direction of the stream is speed downstream. It is given by:
Speed downstream = (A+B) km/hr
And, the speed of the boat against the stream is speed upstream. It is given by:
Speed upstream = (A-B) km/hr

2) Speed of boat in still water is given by;
= 1/2 ( speed downstream + speed upstream)

3) Speed of the stream is given by;
= 1/2 ( speed downstream – speed upstream)

4) A man rows at a speed of X km/hr in still water. If the speed of the stream is Y km/hr and the man rows the same distance upstream and downstream, his average speed for the entire journey is measured by;

5) A man rows a boat in still water at speed of X km/hr. If the stream is flowing at Y km/hr it takes him T hours more to row upstream than to row downstream to cover the same distance. The distance is measured by:

6) A man swims in still water at the speed of X km/hr. If the stream is flowing at Y km/hr it takes him T hours to reach a certain place and then returning back to the starting point. The distance between that place and the starting point is measured by:

7) A boat covers a distance downstream in T1 hours and returns the same distance upstream in T2 hours. If the speed of the stream is Y km/hr, the speed of a boat in still water is measured by:

8) A boat takes K times as long to move upstream as to move downstream to cover a certain distance. The speed of the stream is Y km/hr, the speed of the boat in still water is measured by:

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