It took travis 2.5 hours to complete 3/4 of his trip. he traveled the remaining 52.5 miles in 1 hour. find his average speed for the whole trip.( show steps! )

To find the average speed, we need to find his speed during 3/4 of the trip and then the 52.5 miles. 
So you know that 52.5 is 1/4 of his total trip. That means if we multiply that by 3, that's how many miles he traveled in 2.5hrs. (157.5)
To calculate speed, divide distance by time. 
For 3/4 of his trip (157.5), it took him 2.5 hours. 
157.5/2.5 = 63mph
For the remaining 52.5 miles, it took him an hour.
52.5/1 = 52.5mph
Now average those two speeds to get the average speed for the whole trip.
(63+52.5)/2= 57.6mph