Train A crosses train B running in the same direction in 67.5 seconds and the speed of train A and B is in the ratio of 3:2 respectively. If the difference between the speed of train A and B is 24 kmph, then what is the time taken by train A to cross train B running in the opposite direction?
a) 14.4 seconds
b) 18 seconds
c) 13.5 seconds
d) 12.8 seconds
e) Cannot be determined
Sol:
Speed of train A = 3/1 * 24 = 72 kmph
Speed of train B = 2/1 * 24 = 48 kmph
Length of train A = x
Length of train B = y
x + y = 24 * 5/18 * 67.5
x + y = 450
Required time = 450/((5 * 24) * 5/18) = 13.5 seconds