<PRE><B>Question 331763</B>

train B passes the station after 12 minutes
 Train A speed is 80mph
so in 12 minutes Train A  travels 12/60 *80
=16 miles.
..
train B speed = 100 mph. Train A speed speed 80 mph
so it catches up 20 miles per hour ( 100-80)
20 miles it catches up in 1 hour
16 miles it will catch up in ? 

16/20 hours
4/5 hours.
4/5 * 60 minutes
=48 minutes.
..
Train B passes the station at 6.27 am
add 48 minutes to 6.27 am
it catches up at 7.15 am</PRE>