interstate 25 and interstate 40 meet at a right angle in central Albuquerque (NM). At noon one day, Professor Greenbottle was driving north on Interstate 25 at 70 mph, and 3 miles south of the intersection. At the same time, a Mafia hit squad was driving west on interstate 40 at 50 mph and was 4 miles west of the intersection. Were Professor greenbottle and the mafia hit squad getting closer together or further apart? At what rate?