Question 1171001
The average speed of the bus = 27 mph. The travel time to work is 
55 - 15 = 40 mins. 
Thus the distance to work = d = v*t = 27 mi/h * (40/60)h = 18 miles
The drive home took 24/60 = 2/5 h, so the average speed = 18/(2/5) = 45 mph