Quantitative Aptitude Formulas ( PROBLEMS ON TRAINS )

PROBLEMS ON TRAINS ; IMPORTANT FORMULAE

1. a km/hr = [a * 5/18]m/s.

2. a m/s = [a * 18/5] km/hr.

3. Time taken by a trian of length l metres to pass a pole or a standing man or a signal post is equal to

the time taken by the train to cover l metres.

4. Time taken by a train of length l metres to pass a stationary object of length b metres is the time

taken by the train to cover (l + b) metres.

5. Suppose two trains or two bodies are moving in the same direction at u m/s and v m/s, where u>v,

then their relatives speed = (u - v) m/s.

6. Suppose two trains or two bodies are moving in opposite directions at u m/s and v m/s, then their

relative speed is = (u + v) m/s

7. If two trains of length a metres and b metres are moving in opposite directions at u

8. If two trains of length a metres and b metres are moving in the same direciton 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.

9. If tow 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).