Suppose a plane flies from San Antonio, TX to Phoenix, AZ, a total distance of 1000 miles. Assume the plane makes
a 30-minute stop in El Paso, which directly between the two cities, 400 miles from San Antonio. When the plane
gets to Phoenix, it is instructed to circle the airport while awaiting clearance to land, and it must circle for 30
minutes. The entire trip, from liftoff in San Antonio to touchdown in Phoenix, takes 4 hours. Let