Aptitude Problems On Trains Tutorials & Tricks

Problems On Trains Tutorials & Tricks

Introduction

Train problem moving in some direction with some speed. Problem solving interesting question realted to trains.

Formula for finding out problems on train

1. km/hr to m/s conversion: a km/hr = (a*(5/18))m/s.

2. m/s to km/hr conversion: a m/s = (a*(18/5))km/hr.

3. Time taken by a train of length l metres to pass a pole or 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 stationery object of length bmetres is the time taken by the train to cover (l + b) metres.

5. 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.

6. 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.

7. If two trains of length a metres and b metres are moving in opposite directions at um/s and v m/s, then: The time taken by the trains to cross each other = (a + b) sec. (u + v)

8. If two trains of length a metres and b metres are moving in the same direction at um/s and v m/s, then: The time taken by the faster train to cross the slower train = (a + b) sec. (u - v)

9. 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)

10. Speed = distance/time s = d/t

11. velocity = displacement/time v = d/t.

12. Time taken by a train x meters long to pass a pole or standing man or a post = Time taken by the train to travel x meters.

13. Suppose two trains or two objects are moving in the same direction at v1 m/s and v2 m/s where v1 > v2, then their relative speed = (v1 – v2) m/s

14. Suppose two trains or two objects are moving in opposite directions at v1 m/s and v2 m/s , then their relative speed = (v1+ v2) m/s

15. Assume two trains of length x metres and y metres are moving in opposite directions at v1 m/s and v2 m/s, Then The time taken by the trains to cross each other = (x+y) / (v1+v2) seconds

16. 10. Assume two trains of length x metres and y metres are moving in the same direction at at v1 m/s and v2 m/s where v1 > v2, Then The time taken by the faster train to cross the slower train = (x+y) / (v1-v2) seconds

17. Suppose 2 Trains begins at the same time from X and Y towards each other and after crossing they take x & y secs in reaching Y and X correspondingly, then: (X’s speed) : (Y’s speed) = SQRT(y) : SQRT(x)

18. Rule 1: When two trains are moving in opposite diections, then relatve speed will be the addition of their individiual speeds.

19. Rule 2: When two trains are moving in same diection, then relatve speed will be the subtrction of their individiual speeds.

20. Rule 3: On passing a platform by a certain train the net distance travelled is the sum of length of train and the length of platform both.

21. Rule 4: When a train passes through a pole or person standing, net distance travelled to pass is the length of the train

Sample Example

Ex

A train 120 m long is running at the speed of 54 km /hr. Find the time taken it to pass a man standing near the railway track ?

A

 speed of train = [54 * ( 5 / 18 ) ] = 15 m / sec length of train = 120 m , So required time : Time taken = (120/15) = 8 sec. 

Ex

train is moving at a speed of 54 km / hr. If the length of the train is 100 meters, how long will it take to cross a railway platform 110 meters long ?

A

 speed of train = [54 * ( 5 / 18 ) ] = 15 m / sec Distance covered in passing the platform = 100 + 110 = 210 m therefore Time taken = (210/15) = 14 sec. 

Ex

Two trains 125 m and 100 m in length respectively are running in opposite directions, one at the rate of 50 km / hr and the other at the rate of 40 km /hr. At what time they will clear each other from the moment they meet ?

A

 Relative speed of trains = (50 + 40) km / hr = [90 * ( 5 / 18 ) ] = 25 m / sec Total length to be travelled = 125 + 100 = 225 m therefore Time taken = (225/25) = 9 sec. 

Ex

Two trains 110 m and 100 m in length respectively are running in same directions, one at the rate of 100 km / hr and the other at the rate of 64 km / hr. At what time faster train will clear other train from the moment they meet ?

A

 Since trains are running in same direction, so relative speed = 100-64 = 36 km / hr = [ 36 * ( 5 / 18 )] = 10 m / sec Total length to be travelled = 110 + 100 = 210 m therefore Time taken = (210/10) = 21 sec. 

Ex

A train passes a standing pole on the platform in 5 seconds and passes the platform completely in 20 seconds. If the length of the platform is 225 meters. Then find the length of the train ?

A

 Let the length of the train is x meter So speed of train =( x / 5 ) m / sec Also speed of train = ( 225 + x ) / 20 m/sec x/5 = (225+x)/20, therfore x = 75 m.