Two trains of length 250 m and 120 m are 50 m apart. They start moving towards each other on parallel tracks, at speeds 64 kmph and 42 kmph. After how much time will the trains meet? Choose the correct choice from the following choices
A) 15 / 10 B) 17 / 10 C) 16 / 10 D) 18 / 10 E) 16 / 10

Rationale: "they are moving in opposite directions , relative speed is equal to the sum of their speeds . relative speed = ( 64 + 42 ) * 5 / 18 = 7 * 5 = 29.4 mps . the time required = d / s = 50 / 29.4 = 17 / 10 sec . answer : b"
Answer: B