how much time will a train of length 280 m moving at a speed of 72 kmph take to cross another train of length 360 m , moving at 36 kmph in the same direction ?
"the distance to be covered = sum of their lengths = 280 + 360 = 640 m . relative speed = 72 - 36 = 36 kmph = 36 * 5 / 18 = 10 mps . time required = d / s = 640 / 10 = 64 sec . answer : c"
divide(add(280, 360), multiply(subtract(72, 36), const_0_2778))