How long does a train 110 m long running at the speed of 72 km/hr takes to cross a bridge 138 m length?	Choose one:
A) 82.1 sec . B) 12.4 sec C) 19.1 sec . D) 17.1 sec . E) 42.1 sec .

Rationale: speed = 72 * 5 / 18 = 20 m / sec total distance covered = 110 + 138 = 248 m . required time = 248 / 20 = 12.4 sec . answer : b
Answer: B