On the first day of his cross-country trip, Mike drove 100 miles in 2 hours before stopping for lunch. After lunch, he drove 420 miles in 6 hours. What was average speed in miles per hour for his 8 ho

On the first day of his cross-country trip, Mike drove 100 miles in 2 hours before stopping for lunch. After lunch, he drove 420 miles in 6 hours. What was average speed in miles per hour for his 8 hours of driving?