Remember that
the speed is equal to divide the distance by the time
speed=d/t
solve for t
t=d/speed
we have
d=756 miles
speed=180 miles per hour
substitute
t=756/180
t=4.2 hours
4.2 hours=4 hours +0.20 hours
Convert 0.20 hours to minutes
Multiply by 60
0.20 h=0.20*60=12 minutes
so
4.2 hours=4 h 12 min
therefore
A train started from City A to City B at 13:30.
13:30+ 4h 12 min=17:42 hrs