Find the value of X

Two trains of 400 metres and 475 metres in length runs at the speed of 45 km/hr and X km/hr respectively in opposite direction on parallel tracks. The time taken by them to cross each other is 42 seconds, then find the value of X:

  1. 28 km/hr
  2. 30 m/s
  3. 32 m/s
  4. 30 km/hr
Anurag Mishra Professor Asked on 25th October 2015 in Maths.
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1 Answer(s)

Answer: (2) 30 m/s

Explanation:-
According to the question,
(400 + 475)/(45 + X) x 5/18 = 42
875 x 18/5 (45 + X) = 42
175 x 18 /42 = 45 + X
75  = 45 + X
X = 75 – 45
X = 30 m/s

Then, the speed of the train X is 30 m/s.

Hence, the answer is (2) 30 m/s.

Anurag Mishra Professor Answered on 25th October 2015.
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