Answer:
The annual interest rate is 0.018, or 1.8%.
Explanation:
Let r be the annual interest rate, t be the number of years the money was in the account, and I be the amount of interest earned. Since the interest is simple interest, the amount of interest earned is given by the formula I = Prt, where P is the principal, or initial amount deposited. In this case, we know that P = $3000, t = 3.5 years, and I = $262.50. Substituting these values into the formula, we get:
262.50 = 3000r * 3.5
r = 0.018
Thus, the annual interest rate is 0.018, or 1.8%.