For 3 years, regular weekly payments of 50 are deposited into an account that compounds interest weekly.If the final value of the account is 8600, what was the interest rate? Select one: a. 6.43% b. 6.51% C. 6.45% d. 6.23%

Here's how to solve this problem:**1. Determine the total number of payments:*** There are 52 weeks in a year.* Over 3 years, there are 3 * 52 = 156 weekly payments.**2. Use the future value of an ordinary annuity formula:**The future value (FV) of an ordinary annuity is given by:FV = P * [((1 + r)^n - 1) / r]Where:* FV = Future Value ( 50)* r = Interest rate per period (weekly rate, which we need to find)* n = Number of periods (156)**3. Solve for 'r':** This equation is difficult to solve algebraically. We'll use an iterative approach or a financial calculator.**Iterative Approach (Trial and Error):**We can test the given answer choices to see which one gets us closest to 50 * [((1 + 0.0012365)^156 - 1) / 0.0012365] ≈ 50 * [((1 + 0.0012519)^156 - 1) / 0.0012519] ≈ 50 * [((1 + 0.0012404)^156 - 1) / 0.0012404] ≈ 50 * [((1 + 0.0011981)^156 - 1) / 0.0011981] ≈ 8613.55, which is very close to the target of $8600.**Therefore, the answer is b.**