13
Q:
A) 500 | B) 400 |
C) 360 | D) 480 |
Answer: B) 400
Explanation:
Explanation:
Speed of train 1 = 48 kmph
Let the length of train 1 = 2x meter
Speed of train 2 = 42 kmph
Length of train 2 = x meter (because it is half of train 1's length)
Distance = 2x + x = 3x
Relative speed= 48+42 = 90 kmph = (90*5/18) m/s = 25 m/s
Time = 12 s
Distance/time = speed
=>3x/12 = 25 (25*12)/3
Length of the first train = 2x = 200 meter
Time taken to cross the platform= 45 s
Speed of train 1 = 48 kmph = 480/36 = 40/3 m/s
Distance = 200 + y [where y is the length of the platform]
x =100m => 200+y = 45* 40/3
y = 400m