- QUESTION
A train travelling at 48 km/h completely crosses another train having half the length of first train and travelling in opposite direction at 42 km/h in 12 seconds. The train having speed 48 km/h also passes a railway platform in 45 seconds. What is the length of the platform?
A)600M
B)200M
C)400M
D)200M
Explanation
(C)
=400 m
The correct option is B 400 m
Let the length of first train be x metres.
Then, the length of second train is (x / 2) metres. Relative speed = (48+42) kmph
= (90 * 5/18) * m /sec=25 m/sec.
/(x + x/2)/25 = 12 OR (3x)/2 = 300
or x = 200
.. Length of first train = 200m Let the length of platform be y metres.
Speed of the first train
=(48×5/18)m/sec40/3 M/SEC
(200 + y) * 3/40 = 45
600 + 3y = 1800
y = 400m
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