The following table shows the average returns for some of the largest mutual funds commonly found in retirement plans. (Assume end-of-month deposits and withdrawals and monthly compounding, and assume that the quoted rate of return continues indefinitely.) How mud. with payments of $320 per ated after 25 years in a retirement account invested entirely in the Vanguard 500 stock fund x per month? HINT [See Quick Example 1.] (Round your answer to the nearest cent.)