Two stations A and B are 110 km apart on a straight line. One train starts from A at 7 a.m. and travels towards B at 20 km/h. Another train starts from B at 8 a.m. and travels towards A at a speed of 25km/h. At what time will they meet?

Correct option is D

Given:

Distance between Station A and Station B = 110 km
Speed of Train A = 20 km/h
Speed of Train B = 25 km/h
Train A starts at 7 a.m. and Train B starts at 8 a.m.

Formula Used:
Time taken to meet = Distance / Relative Speed
Relative Speed = Speed of Train A + Speed of Train B

Solution:
By the time Train B starts at 8 a.m., Train A would have already traveled for 1 hour. In this 1 hour, Train A covers a distance of:
Distance covered by Train A in 1 hour = 20 km/h × 1 hour = 20 km
Remaining distance between the two trains = 110 km - 20 km = 90 km
Now, both trains are moving towards each other with a relative speed of:
Relative speed = 20 km/h + 25 km/h = 45 km/h
Time taken to meet after 8 a.m. = Remaining distance / Relative speed = 90 km / 45 km/h = 2 hours
Thus, they will meet 2 hours after 8 a.m., i.e., at 10 a.m.