A train leaves manipur at 6:00 am and reaches Dispur at 10:00 am. Another train leaves Dispur at 8:00 am and reaches Manipur at 11:00 am. At what time do the two trains cross each other?

Let distance between Manipur and Dispur = D km
Average speed of train from Manipur = D/4 km/h
Average speed of train from Dispur = 2D/7 km/h
Let they meet T h after 6:00 am.
Then, according to the question,
(D/4 x T) + 2D/7 x (T - 2) = D
⇒ T/4 + 2(T - 2)/7 = 1
⇒ 7T + 8(T - 2) = 28
⇒ 15T = 44
∴ T = 44/15 h = 2h 56 min
Clearly, trains meet 2 h 56 min after 6:00 am.
It means the trains meet at 8:56 am.