Let’s take the interest rate (5.25%) and multiply it by 63.6 years, we get 3.339. Multiply 3.339 with $7900 (initial amount) and you’ll get $26,378.1 worth of interest money, add $7900 (initial amount) and $26,378.1 (interest money after 63.6 years), you’ll get $34,278.1 which is $34,300 rounded off to the nearest 100.
Therefore the answer to your question might be 70 years as after 63.6 years the account will have more than $34,300, therefore 60 years might not be the answer since then the amount would be lower than $34,300, but at year 70, a tenth of a year, the value in the account will be more than $34,300, so it will have at least reached $34,300 unlike at year 60 when the account value would be lower than $34,300 so it wouldn’t have even reached $34,300.