On a cross-country trip, a couple drives 500 mi in 10 h on the first day, 380 mi in 8.0 h on the second day, and 600 mi in 15 h on the third day. what was the average speed for the whole trip?

We know that the average speed is simply the ratio of the total distance travelled over the total duration of the trip.

total distance = 500 mi + 380 mi + 600 mi

total distance = 1,480 mi

total time = 10 h + 8 h + 15 h

total time = 33 h

So the average speed is therefore:

average speed = 1,480 mi / 33 h

average speed = 44.85 mi / h