—————————————- Choose the Correct Answer ——————————————— A) 120 metres B) 180 metres C) 324 metres D) 150 metres

#### Topic: Problems on Trains

**Formulas**

These formulas will be helpful to you in solving most of the problems on trains that appear in many competitive exams:

- Formula to convert km/hr to m/s is
**X km/hr = (X x 5/18) m/s** - Formula to convert m/s to km/hr is
**X m/s = (X x 18/5) km/hr** - Time taken by a train of length
metres to pass a pole or standing man or a signal post is equal to the time taken by the train to cover**X**meters.**X** - Time taken by a train of length
metres to pass a stationary object of length*X*metres is the time taken by the train to cover**Y***(X + Y) metres.* - When two trains or two objects are moving in the same direction at
m/s and**X**m/s, where**Y****X > Y**, then their relative speed is =**(X – Y) m/s.** - When two trains or two bodies are moving in opposite directions at X m/s and Y m/s, then their relative speed is =
**(X + Y) m/s.** - When two trains of length
metres and**X**metres respectively are moving in opposite directions at**Y**and**A m/s**, then the formula to find the time taken by the trains to cross each other is**B m/s****[(X + Y)/(A + B)] seconds**. - When two trains of length X metres and Y metres are moving in the same direction at A m/s and B m/s, then the formula to find the time taken by the faster train to cross the slower train is
**[(X + Y)/(A – B)] seconds** - When two trains or objects start at the same time from points A and B towards each other and after crossing they take X and Y sec respectively in order to reach points B and A respectively, then the ratio of their speeds will be ==>
**√Y : √X**