$3-$M$.$ A$.$ Bagley plans to retire with $$722,530$ in the bank. The appropriate rate of return is $9\mathrm{.}6\%.$ If Bagley saves $$13,200$ every year starting next year, how soon can Bagley retire?

$3-$N$.$ You need $$77,256$ today and can repay the money in installments of $$9,480$ every year starting next year. If the rate of return is $8\mathrm{.}2\%,$ how long do you expect to take to repay the loan?

Calculating the Interest Rate of an Annuity

$3-0.$ Find the APR on a loan of $$83,770$ for $16$ years, which has a payment of $$840$ every month.