Caroline would earn $64,523 interest on a 3-year CD and $118,403 interest on a 3.5-year CD.
How to solve
Here are the calculations for the interest earned on 3-year and 3.5-year CDs compounded monthly at 1.2%:
3-year CD
Monthly interest rate = 1.2% / 12 = 0.1%
Number of months = 3 years * 12 months/year = 36 months
Future value = Principal * (1 + Monthly interest rate)^(Number of months)
Future value = $519,400 * (1 + 0.001)^(36) ≈ $583,923
Interest earned = Future value - Principal = $583,923 - $519,400 ≈ $64,523
3.5-year CD
Monthly interest rate = 1.2% / 12 = 0.1%
Number of months = 3.5 years * 12 months/year = 42 months
Future value = Principal * (1 + Monthly interest rate)^(Number of months)
Future value = $519,400 * (1 + 0.001)^(42) ≈ $637,803
Interest earned = Future value - Principal = $637,803 - $519,400 ≈ $118,403
Therefore, Caroline would earn $64,523 interest on a 3-year CD and $118,403 interest on a 3.5-year CD.