Final answer:
To reach the total cost of college education in 16 years, an annual rate of interest of approximately 7.64% is needed.
Step-by-step explanation:
Annual Rate of Interest Needed
To calculate the annual rate of interest needed to reach the total cost of the college education, we can use the compound interest formula: A = P(1+r)^n, where A is the future value, P is the present value, r is the annual interest rate, and n is the number of years. In this case, the present value (P) is $67,000, the future value (A) is $405,000, and the number of years (n) is 16. We need to solve for the annual interest rate (r). Rearranging the formula, we have r = (A/P)^(1/n) - 1. Plugging in the values, we get r = (405,000/67,000)^(1/16) - 1. Evaluating this expression, the required annual rate of interest is approximately 7.64%.