Answer:
Adam needs to pay $266.25.
Explanation:
Consider the provided information.
Adam invested $12,000 in a six-year CD that paid 7.1% interest, but later needed to withdraw $2,500 early.
The interest rate is 7.1%.
The monthly interest rate will be:

Now for 18 months the interest will be:

The penalty for early withdrawal was eighteen months’ worth of interest on the amount withdrawn,
The withdrawal amount is 2,500 and the interest for 18 months is 10.65%
2,500×10.65%=25×10.65=266.25
Hence, Adam needs to pay $266.25 as penalty.