A train leaves Mumabai at 9 am at a speed of 45 kmph. After one hour, another train leaves Mumbai in the same direction as that of the first train at a speed of 90 kmph. When and at what distance from Mumbai do the two trains meet? Choose one:
A) 287  B) 279  C) 90  D) 278  E) 379

Rationale: "when the second train leaves mumbai the first train covers 45 * 1 = 45 km so , the distance between first train and second train is 45 km at 10.00 am time taken by the trains to meet = distance / relative speed = 45 / ( 90 - 45 ) = 1 hours so , the two trains meet at 2 p . m . the two trains meet 1 * 90 = 90 km away from mumbai . answer : c"
Answer: C