Find the final amount (rounded to the nearest dollar) in this retirement account, in which the rate of return on the account and the regular contribution change over time. $400 per month invested at 6%, compounded monthly, for 15 years: then $700 per month invested at 7%, compounded monthly, for 15 years. About $564, 777 About $338, 201 About $553, 284 About $901, 200