In 1972, Bob purchased a new Datsun 240Z for $3,000. Datsun later changed its name to Nissan, and the 1972 240Z became a classic. Bob kept his car in excellent condition and in 2002 could sell the car for six times what he originally paid. What was Bob's return on owning this car? What if he keeps the car for another thirty years and earns the same rate? What could he sell the car for in 2032 ?