5-43. Toyota will bring hybrid electric automobiles to market next year priced at $30,000 (this includes a $7,500 federal tax credit). At $2.00 per gallon of gasoline, it will take 10 years to recoup the difference in price between a base model Toyota Camry and its four-cylinder gasoline-only counterpart. The price difference is $3,720. If the hybrid vehicle is driven for 15 years, what is the internal rate of return on the extra investment in the hybrid? (5.6)