How long does a train 100 m long traveling at 72 kmph takes to cross a tunnel of 1400 m in length?
Answers
A) 70 sec  B) 60 sec  C) 82 sec  D) 75 sec  E) 62 sec

Rationale: d = 1400 + 100 = 1500 m s = 72 * 5 / 18 = 20 t = 1500 * 1 / 20 = 75 sec answer : d
Answer: D