A train leaves Mumabai at 9 am at a speed of 40 kmph. After one hour, another train leaves Mumbai in the same direction as that of the first train at a speed of 60 kmph. When and at what distance from Mumbai do the two trains meet?
Choose the correct choice from the following answers.
A) 187  B) 279  C) 120  D) 278  E) 379

Rationale: "when the second train leaves mumbai the first train covers 40 * 1 = 40 km so , the distance between first train and second train is 40 km at 10.00 am time taken by the trains to meet = distance / relative speed = 40 / ( 60 - 40 ) = 2 hours so , the two trains meet at 12 a . m . the two trains meet 2 * 60 = 120 km away from mumbai . answer : c"
Answer: C