Problem $5-13$ Future Value of Multiple Annuities $($LG$5-2)$

Assume that you contribute $$290$ per month to a retirement plan for $20$ years. Then you are able to increase the contribution to $$580$ per month for another $30$ years. Given a $7\mathrm{.}2$ percent interest rate, what is the value of your retirement plan after the $50$ years?

Note: Do not round intermediate calculations and round your final answer to $2$ decimal places.

Answer is complete but not entirely correct.

$\backslash$table$[[$Future value of multiple annuities,$$3,907,249,94]]$