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Wednesday, July 15, 2015

Simple and Shortcut Trick & Concept to Solve Boat and Stream

                                          Boat and Stream

To understand Boat and Stream topic you need to understand four Basic topic

1) Speed of a Boat in Still Water
2) Speed of Stream
3) Boat Upstream Speed
4) Boat Downstream Speed.

Once you understand this four topic you will able to solve any problem on boat and stream.

To understand Boat and Stream you need to understand what is upstream speed and downstream speed ?

Boat Speed : Speed of a Boat in still Water.
Stream Speed : Speed of Water, it can add and Subtract from its speed.

Let us assume that you are the Boat,  Boat Speed at U km/hr and Stream Speed at V km/hr.

Lets take 1st condition
(1) You are riding up the stream and now the speed is flowing Downwards,  so there Stream speed            is V km/hr,  but boat is going Up Direction mean Stream is opposing your Force is U.

So the   Upstream Speed = (U - V ) km/hr.

(2)   When you take a Down Stream Speed, you are riding in the flow of water, so this gives an                    additional Boost, its like Riding a Cycle Down on Hill.

         Downstream Speed = (U + V)  km/hr.

So Now take  Boat Speed = U km/hr and  Stream Speed = V km/hr.

  Then  Down Speed =  U + V  ---------------- a km/hr denote Downstream Speed.
        Upstream Speed = U – V ----------------- b km/hr denote Upstream Speed.

On some problem they give you Downstream and upstream speed and you have to find your Stream speed and Boat Speed,  so this step will help you to do that.

Stream Speed = ( Downstream - Upstream)/2  =  ( a-b)/2  km/hr
Boat Speed = ( Upstream + Downstream )/2 =  ( a+b)/2  km/hr.

This formulas you can use Directly and Find out the answers.

 Lets Take a Simple Example.
Example 1: A man can row Upstream at 7 kmph and Downstream at 10 kmph. Find the man’s rate in still water and rate of the Current ?

Solution :- So this is the Comparatively easy Problem.
                   They given us, Downstream ‘a’ = 10 km/hr.                                                                                                                                      
                                            Upstream  ‘ b’ = 7 km/hr.

we have to find
 (1) Speed in Still water (Boat Speed) = (Upstream + Downstream)/2 = (a+b)/2.
                                =  (  10+7)/2 = 17/2 =  8.5 km/hr.

(2)  Speed of Current (Stream Speed) = (Downstream - Upstream)/2 = (a-b)/2 .
                                = ( 10-7)/2  = 3/2  = 1.5 km/hr.