Final answer:
Sue will have approximately $537.77 after 8 years of investing $280 at an 8.5% annual interest rate with annual compounding. The correct option is a.
Step-by-step explanation:
To calculate how much Sue will have after 8 years if she leaves it invested at 8.5% with annual compounding, you can use the formula for compound interest: A = P(1 + r/n)^(nt), where A is the amount of money accumulated after n years, including interest, P is the principal amount (the initial amount of money).
r is the annual interest rate (decimal), n is the number of times that interest is compounded per year, and t is the time the money is invested for in years. In Sue's case, P = $280, r = 8.5% or 0.085, n = 1 (since the interest is compounded annually), and t = 8 years.
Plugging these values into the formula we get: A = $280(1 + 0.085/1)^(1*8) = $280(1 + 0.085)^8 = $280(1.085)^8 ≈ $537.77. Therefore, the correct answer is a. $537.77.