must show work without excel

Sherri oues $5,500 on her credit card. The card has aa AlR of I4 9 porcent. Shem bas decided not to charge any additional purchases becaase sbe wants to get this debt paid in fitl. A) How must longer will it take ber to pay off this balance if sho makes monthly psyments of $70 rather than $80?. B) What is her total interest payment in both cases