Important Formulas

1.    Speed = Distance / Time

So    Distance= Speed  X  Time        and     

        Time = Distance / Time    

2. Conversion of Km/hr to m/sec : 

     m km/hr  =  m X (5/18)

3. Conversion of m/Sec to Km/hr : 

     m m/sec  =  m X (18/5)

4. When a train crosses a single post or standing man or a tree, the train will move a distance equal to the length of the train. So the time time taken by the train on those situation is = (Length of the train)/(Speed of the train)

5. When a train need to cross a platform or a bridge, the train have to cross the distnace equal to the sum of the length of the train and bridge. So the Time taken by the train to cross a platform or bridge =

                            Length of Train + Length of Platform(Bridge) / Speed of Train

6. If two trains (or a train and an object ) of length a meters and b meters move in the same direction with the speed of X m/s and Y m/s respectively, where X>Y then their relative speed is = (X-Y) m/s and Time time taken the fater trains to cross the slower train is =

                                 (a + b) / (X-Y)

7. If two trains (or a train and an object ) of length a meters and b meters move in the opposite direction with the speed of X m/s and Y m/s respectively, where X>Y then their relative speed is = (X+Y) m/s and Time time taken to cross each other is =

                                (a + b) / (X+Y)

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