You graduate and receive a $10000 cheque from your grandparents. You decide to save it toward a down payment on a house. You invest it earning 6% per year, and you think you will need to have $20000 saved for the down payment. How long will it be before the $10000 has grown to $20000? To double the money you received from your grandparents, it will take____ years. (Round to one decimal place.)