PROBLEMS ON TRAINS

*Time taken by train '𝓧' metres long in passing a signal post or a pole or standing man= Time taken by the train to cover '𝓧' meters (ie its length)

*Time taken by train '𝓧' metres long in passing a stationary object (e.g tunnel ,paltform,bridge) of length '𝓨' metres =Time taken by the train to cover (𝓧+𝓨) metres (ie length of train+length of the object)

*If two trains of length '𝓧' km and '𝓨' km are moving in the same direction at speed 'U' km/h and V km/h where U>V ,Then the time taken by the faster train to cross the slower train =❲𝒙+𝗒/u-v).


SOLVED QUESTIONS

1.A train is 125 m long .If the train take 30 seconds to cross a tree standing by the railway line ,the speed of train in Km/Hr  is ..?

Speed =distance/time
           =125/30 m/s
           =125/30 𝖷 18/5 km/hr =15 km/hr.
Answer:15 km/hr

2.A train 280 m long is moving at 60 kmph.The time taken by the train to cross a tunnel 220 m long is ..?

Speed= (60×5⁄18) m/s
          = (50/3) m/s

Distance covered =(280+220)m=500 m

So Required time= 500÷ 50/3 = 500𝖷3/50=30 seconds

Answer: 30 seconds


3.A train 300 m long crossed a platform 900 m long in 1 minute 12 seconds.The speed of the train (in km/hr ) is ..?

Total distance covered = (300+900)m= 1200 m

Time taken =1 min.12 second=72 second

So Speed = ❲1200/72❳ m/sec

                = ❲1200/72  𝖷 18/5❳km/hr = 60 km/hr

 Answer: 60 km/hr

4.A train runs at a speed of 90 km/hr.The speed of the train in metre per second is ?
A)20
B)25
C)40
D)50

90 km/hr =90x5/18 m/s= 25 m/s

Answer: 25m/s


5.A train  110 m long takes three seconds to pass a standing man. How long is the platform if it passes through it in 15 seconds moving with the same Speed?

A)440 m

B)400 m

C)550m

D)450 m

Speed of the train =distance/time =110/3 m/s.

If the length of the platform = 𝓧 metres, distance travelled by the train in passing through it?

= (110+x)m =, Now 110+x ÷ 110/3=15; 

;110+x =110/3 ✖ 15;  X= 550-110 =440

Answer:440

6.A train crosses a telegraph pole in 6 seconds and a 220 metres long bridge in 16 seconds. The speed (in m/sec) of the train is ..?

Let the length of train =𝒳 m.

Speed when passing the telegraph pole= 𝒙/6 m/s

Speed when passing the bridge =❲𝒙+220/16❳m/s.

Since speed are the same  ,𝒳/6= 𝒙+220/16

                                                  

                                                 =16𝒙 = 6𝒙+6𝖷220

                                                 ➤16𝓍-6𝒙 1320; 𝒙 = 132

                                                 ➤𝒙/6= 132/6  =22 m/s

Answer:22 m/s

Simple Interest

Time and Work

Solved Maths

Letter Classification

Reasoning

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