Dave Kaminsky bought a Ford Mustang seven years ago for £ 32,000. He has decided to sell it as he now needs a pıck-up truck for his new business. He received £ 12,000 for it from a dealer in part exchange, which means that since the price of the Ford Mustang was more than that of a pick-up truck, Dave received £ 12,000 and the pick-up truck in exchange for his Ford Mustang. What was his rate of return for this transaction?