Two stations A and B are 200 km apart on a straight line. One train starts from A at 7 a.m. and travels towards B at 20 kmph. Another train starts from B at 8 a.m. and travels towards A at a speed of 25 kmph. At what time will they meet? Choose the correct choice from the following.
A) 9
B) 10
C) 11
D) 12
E) 8
Suppose they meet x hours after 7 a.m.   Distance covered by A in x hours = 20x km.   Distance covered by B in (x - 1) hours = 25(x - 1) km.   Therefore 20x + 25(x - 1) = 200   45x = 225   x = 5.   So, they meet at 12 a.m.   Answer: Option 12
<result>D</result>
Two stations A and B are 200 km apart on a straight line. One train starts from A at 7 a.m. and travels towards B at 20 kmph. Another train starts from B at 8 a.m. and travels towards A at a speed of 25 kmph. At what time will they meet?