Answer: The formula for compound interest is A = P(1 + r/n)^(nt) where A is the amount, P is the principal (initial deposit), r is the interest rate, t is the time in years, and n is the number of times compounded per year.
To find out how many years it will take for the money to grow to 500 naira, we can set A equal to 500, P equal to 400, r equal to 5% (or 0.05), and n equal to 1 (since the interest is compounded annually).
Plugging these values into the formula, we get:
500 = 400(1 + 0.05)^t
By solving this equation, t = 3.32 years.
So, it will take 3.32 years for the money in the savings account to grow to 500 naira.
Explanation: