Fourteen years ago, your uncle opened an investment account to pay for your college education. He was supposed to put $3,000 in the account at the end of each year, but in year 6, he forgot to make a deposit. In year 8 he put $6,000 instead. If the account pays an annually compounded interest rate of 7%, how much money is there now? (all deposits are made at the end of the year, including the first one).

This is my work. I think I did almost everything right, but I was confused about year 8 because I think my value is off there. Can you explain how to get a more accurate value? Thank you!

Year Payment APR Yearly Payment With Interest 1 2 3 4 5 6 7 $3.000 $3,000 $3,000 $3,000 $3,000 $0 $3,000 $6,000 $3,000 $3,000 $3,000 $3.000 $3.000 $3,000 7% 7% 7% 7% 7% 7% 7% 7% 7% 7% 7% 7% 7% 7% Annually Compounded Interest Rate 1.0000 1.0700 1.1449 1.225 1.3108 1.4026 1.5007 1.6058 1.7182 1.8385 1.9672 2.1049 2.2522 2.4098 $3,000 $3,210 $3,434.70 $3,675.13 $3.932.39 $0.00 $4,502.19 $9,634.80 $5,154.56 $5,515.38 $5,901.45 $6,314.56 $6.756.57 $7.229.54 8 9 10 11 12 13 14