The distance between two station 'X' and 'Y' is 450 km. A train L starts at 6:00 pm from X and moves towards Y at an average speed of 60 km/h. Another train M starts from Y at 5:20 pm and moves towards X at an average speed of 80 km/h How far from X will the two trains meet and at what time?

Let two trains meet at a km from 'X'
[Time taken by M to cover (450 - a)km] - [Time taken by the L to cover a km ] = 40/60
⇒ (450 - a)/80 - a/60 = 40/60
⇒ (450 - a)/80 = 40/60 + a/60
⇒ (450 - a)/8 - (a + 40) / 6 = 0
⇒ 3(450 - a) - 4(a + 40) = 0
⇒ 7a = 1190
∴ a = 1190 / 7 = 170
Time taken by L to cover 170 km = 170/60 h = 2 h 50 min
So, the two trains will meet 2 h 50 min after 6:00 pm. it means that the two trains will meet at 8 : 50 pm .