Two trains 200 m and 150 m long are running on parallel rails at the rate of 40 kmph and 48 kmph respectively. In how much time will they cross each other, if they are running in the same direction?  Choose the correct option
A) 72 sec
B) 132 sec
C) 157.5 sec
D) 252 sec
E) none

Rationale: "solution relative speed = ( 48 - 40 ) kmph = 8 kmph = ( 8 x 5 / 18 ) m / sec = ( 40 / 18 ) m / sec time taken = ( 350 x 18 / 40 ) sec = 157.5 sec . answer c"
Answer: C