Answer:
To compute the average speed, multiply the total distance travelled by the whole time spent. There's a formula for speed, time and distance
Travel distance aboard the pterodactyl = 10 mph x 3 hours = 30 miles
Distance travelled on the spinosaurus = 2 miles x 1 hour = 2 miles
30 miles + 2 miles = 32 miles total distance travelled
Total time required = 3 hours + 1 hour = 4 hours
Average speed = total distance travelled divided by the total time taken = 32 miles divided by 4 hours = 8 mph
As a result, our average speed is 8 mph.