Question

Upon retirement (40 years from now) you want to receive "4,000" (amount of money you choose in Part a) each month for a period of 28 years. This money resides in an account that pays 5.8% interest. How much money must be in the account to fulfill your goal?

Answer 1

In order to use our standard compound interest formulas, the payment period must be the same as the compounding period of the interest rate, so I will assume you meant 5.8% per annum compounded monthly.
i = .058/12 = .00483333...
present value of what is needed now .... P
Pick 40 years from now as the focal date

P(1.00483333...)^480 = 4000(1 - 1.00483333..^-336)/.00483333...
(I stored .0048333.. in my calculator's memory, thus keeping the best accuracy possible )

P(10.11896447) = 663,822.3742
P = $65,601.81