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2 years ago

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The length of a Train A is 480 m and it takes 2 minutes to cross a tunnel of length 1,320 m. The length of a Train B, which is s

lower than Train A, is 420 m. Both the trains start at the same time from the opposite directions. If the difference between their speeds is 18 km/h, find the time they take to cross each other. (Enter only the number)

1 answer:

nasty-shy [4]2 years ago

4 0

Answer: 52.94

Step-by-step explanation:

Length of train A = 480m

Tunnel length = 1320m

Time taken to cross tunnel = 2 mins = 120sec

Length of train B = 420m

Train B is slower than train A

Difference between their speed = 18km/hr

18km/hr = (18×1000)/3600 = 5m/s

Speed of train A :

Speed = distance / time

Speed = 1320 / 120 = 11m/s

Therefore, speed of train B :

(11 - 5)m/s = 6m/s

Relative speed of the two trains is therefore;

(Speed of A + speed of B)

Note : they are moving in opposite direction

( 11 + 6)m/s = 17m/s

Therefore time taken to cross each other :

(Sum of the length of both trains / relative speed of the trains)

Time taken = (480m + 420m) / (17m/s)

Time taken = 900m / 17m/s

Time taken = 52.94s

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