Final answer:
The effective annual rate for the First National Bank card is approximately 21.94%, while for the First United Bank card it is 21%. The EAR tells us the actual interest borrowers will pay, which is higher than the stated APR due to the compounding effect.
Step-by-step explanation:
The student is asking about calculating the effective annual rates (EAR) for two different credit card interest scenarios with the same Annual Percentage Rate (APR) of 20%. For the first card from First National Bank, the interest is compounded monthly at a rate of 1.667%. An EAR calculation for this would be ((1 + 0.01667)^12 - 1) which equals approximately 21.94%. The second card from First United Bank compounds interest semiannually at 10%. The EAR for this would be ((1 + 0.10)^2 - 1), which equals 21%. Both banks, particularly national ones, can match these rates, but the actual cost to the borrower is more accurately reflected in the EAR rather than the advertised APR.