Answer Happy

A man was unemployed for 7.26152224 months and accumulated
$17984.37 of credit card debt. The nominal annual interest
rate on this credit card account is 21.78457%, compounded monthly.
Now that he is employed, the man plans to pay off this debt
in four years by (i) no longer making any purchases using this card
and (ii) making regular monthly payments.
(a) What is the effective annual interest rate being charged on
the credit card account?
Effective annual interest rate: Blank 1. Calculate the
answer by read surrounding text. %
(b) What monthly payment is needed in order to fully pay
off this debt in exactly four years?
Monthly payment: $ Blank 2. Calculate the answer by read
surrounding text.
(c) Assuming the man makes the monthly payments as
scheduled, how much will be owed on the debt after 12 payments are
made?
Amount remaining on debt: $ Blank 3. Calculate the
answer by read surrounding text.