In this video, we tackle a complex perpetuity problem involving a series of payments spaced every three years. The task is to determine the missing cash flows (denoted as "x") based on the given present value and annual discount rate. The key to solving this problem is grouping repeating cash flow patterns into one singular payment, which can then be analyzed using perpetuity formulas. We start with the present value and the perpetuity formula (Present Value = Payment / Discount Rate). We identify that the payments repeat every three years, which leads us to group the payments accordingly. The challenge is in finding the appropriate rate for the three-year period, which requires using the formula for the effective period rate. By calculating the rate for three years and applying it to the perpetuity formula, we derive the missing cash flow value. The video also explains how to compute the effective period rate for different compounding frequencies, ensuring a clear understanding of how interest is applied over extended periods. This problem provides essential practice for mastering perpetuities and handling more advanced finance questions.