Final answer:
Earl must invest approximately $128,834 today to meet his $380,000 goal. Option b is correct.
Step-by-step explanation:
To find out how much Earl must invest today to meet his $380,000 goal, we can use the formula for compound interest: A = P(1+r/n)^(nt).
A = the future value of the investment, which is $380,000.
P = the principal amount, which is what we need to find.
r = the annual interest rate, which is 10% or 0.10 in decimal form.
n = the number of times the interest is compounded per year, which is semiannually or 2 times per year.
t = the number of years, which is the difference between Earl's retirement age (65) and his current age (52), so t = 65 - 52 = 13 years.
Substituting these values into the formula, we get:
$380,000 = P(1+0.10/2)^(2*13)
Simplifying the equation:
$380,000 = P(1.05)^26
Dividing both sides of the equation by (1.05)^26:
P = $380,000 / (1.05)^26
Using a calculator, we find that P is approximately $128,834.
Therefore, Earl must invest approximately $128,834 today to meet his $380,000 goal. Option b is correct.