+743 If Mark drives for 4 hours at 60 miles per hour and then drives another 8 hours at 45 miles per hour, what is his average speed, in miles per hour, for the trip?
+6 Mark drives 240+360=600 miles for the whole trip. It took him 12 hours in total and that gives an average of 600/12= 50 mph for the trip.
+13 In 4 hours at 60 miles per hour, he travels 4 hours * 60 miles per hour = 240 miles. In 8 hours at 45 miles per hour, he travels 8 hours * 45 miles per hour = 360 miles. In total, he travels 240 miles + 360 miles = 600 miles. In total, he drives for 4 hours + 8 hours = 12 hours. Therefore, his average speed is 600 miles / 12 hours = 50 miles per hour. So the answer is 50
