Answer:
30 mph
Step-by-step explanation:
The average speed = Total distance / Total Time
Distance at 45 m/hr.
t = 20 minutes = 20/60 = 1/3 hour.
r = rate = 45 miles / hour
d = r * t
d = 45 * 1/3 = 15 miles.
Average Speed going home.
t = 30 minutes
t = 30 min / 60 min // hour = 1/2 hours
r = 15 miles / 1/2 = 15 * 2 = 30 miles / hr.