Answer:
Average speed = 65 miles per hour
Explanation:
Mike drove 100 miles in 2hrs
He stopped to take lunch then;
drove 420 miles in 6hrs
Total distance covered = 100 + 420 miles = 520 miles
Total time taken = 2 + 6 hrs = 8hrs
Average speed = Total distance ÷ total time = 520/8 = 65 miles per hour