Answer:
55 miles per hour
Step-by-step explanation:
given the originally traveled 40 miles in one hour gives us 40 mph, 180 miles in the last 3 hours gives us an average of 60 mph for the second part, 40+60+60+60 (for the 3 hours going that fast) is equal to 220, divide that by 4 to give us our average of 55 mph
