D = 1400+100 = 1500 m
S = 72 * 5/18 = 20
T = 1500 * 1/20 = 75 sec
How long does a train 100 m long traveling at 72 kmph takes to cross a tunnel of 1400 m in length?
A. 70 sec
B. 60sec
C. 82 sec
D. 75 sec
E. 62 sec