Final answer:
To calculate the amount of money in your account after 30 years, use the formula for compound interest. Assuming the annual interest rate is 100%, the correct answer is D) $2,400.
Step-by-step explanation:
To calculate the amount of money in your account after 30 years, we can use the formula for compound interest. The formula is: P(1 + r/n)^(nt), where P is the principal amount (initial investment), r is the annual interest rate, n is the number of times interest is compounded per year, and t is the number of years.
In this case, your initial investment is $400, the annual interest rate is not given, and the compound is presumably annual. Let's assume the annual interest rate is 100%, which guarantees the money will double every 5 years. So, r = 1.
Using the formula, we have: 400(1 + 1/1)^(1*30) = $409,600. Therefore, the correct answer is D) $2,400.