Two trains 200 m and 180 m long are running on parallel rails at the rate of 40 kmph and 45 kmph respectively. In how much time will they cross each other, if they are running in the same direction?
Choose the correct choice from the following options
A) 72 sec B) 132 sec C) 192 sec D) 273.6 sec E) none

Rationale: "solution relative speed = ( 45 - 40 ) kmph = 5 kmph = ( 5 x 5 / 18 ) m / sec = ( 25 / 18 ) m / sec time taken = ( 380 x 18 / 25 ) sec = 273.6 sec . answer d"
Answer: D