12. The interest due will be I = Prt = (1.0565·$12,465.00-1300.00)·0.064·(1/12) = $63.30 . . . . correct
13. The interest due will be I = Prt = (1.0565·$12,465.00-1500.00)·0.05·(1/12) = $48.62 Then your savings is $63.30 -48.62 = $14.68 . . . . correct
14. The balance is 3489.90/5000.00 ≈ 69.8% of the card's credit limit. We do not know the "acceptable debt ratio percentage", so we cannot answer how much over that ratio this balance might be. (Usually such a debt ratio would be the ratio of total debt to income. Knowing just the credit card debt is insufficient information.)
