Mr. Smith was driving 50 mph for the first two hours of his trip, then 60 mph for the remaining three hours. What was the average speed for the whole trip?
For the first two hours, he drove at 50 mph:
Distance = Rate x Time ---> Distance = 50 mph x 2 hrs = 100 miles
For the next three hours, he drove at 60 mph:
Distance = 60 mph x 3 hours = 180 miles
Total distance = 280 miles Total time = 5 hours
To find the average speed:
Distance = Rate x Time
280 mi = Rate x 5 hours (divide both sides by 5 hours)
56 mph = Rate