Important Formula's to solve Train Problems (Speed,Distance and Time) - Theory

I. 

1) Distance = Time X Speed (D = T X S)

2) Time =  Distance / Speed  (T=D/S)

3) Speed = Distance / Time   (S=D/T)

II.  When a train crosses a person or when a train crosses a pole:

  Time taken by train to cross = Length of the train / Speed of the train
           ** T = L/S 

III. When a train crosses a platform or a river:

Time taken by train to cross = Length of train+ Length of Platform

                                                             Speed of the train

         ** T = Lt+Lp
                       S  
               

IV.  When a train cross another train comping in opposite  direction:

Time taken by train to cross = Length of 1st train + Length of 2nd train

                                                 Speed of the 1st train + Speed of 2nd train
            ** T = L1+L2
                         S1+S2   

V. When a train crosses another train going in the same direction: 

Time taken to cross other train = Length of 1st train + Length of 2nd train

                                                     Speed of the 1st train - Speed of 2nd train

           ** T = L1+L2

                        S1- S2   

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