# Problems On Trains – Aptitude Tricks & Shortcuts & Formulas

Important Formula :

1.To convert from km/hr to m/sec :    Multiply by 5/18  m/s.

2.To convert from m/sec to Km/hr :    Multiply by 18/5  km/hr.

3. Formulas for finding Speed, Time and Distance

4. Time taken by a train of length L meters to pass a pole or standing man or a signal post is equal to the time taken by the train to cover L meters.

5. Time taken by a train of length l meters to pass a stationery object of length b meters is the time taken by the train to cover (l + b) meters.

6. Suppose two trains or two objects bodies are moving in the same direction at u m/s and v m/s, where u > v, then their relative speed is = (u – v) m/s.

7. Suppose two trains or two objects bodies are moving in opposite directions at u m/s and v m/s, then their relative speed is =  (u + v) m/s.

8. If two trains of length a metres and b metres are moving in opposite directions at u m/s and v m/s, then:

The time taken by the trains to cross each other = (a + b)/(u + v) sec.

9. If two trains of length a metres and b metres are moving in the same direction at u m/s and v m/s, then:

The time taken by the faster train to cross the slower train = (a + b)/(u – v) sec.

10. If two trains (or bodies) start at the same time from points A and B towards each other and after crossing they take a and b sec          in reaching B and A respectively, then:

(A’s speed) : (B’s speed) = ( b : a)

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