Joe deposits 20 today and another 40 in six years into a fund paying simple interest of 10% per year. Tina will make the same two deposits, but the 20 will be deposited n years from today and the 40 will be deposited 2n years from today. Tina's deposits earn an annual effective rate of 8% . At the end of 12 years, the accumulated amount of Tina's deposits equals the accumulated amount of Joe's deposits. Calculate n.