老师您好，请问这题中的discounted payback period有没有直接用计算器计算的简易方法？还是只能使用答案里列表一个个算这个方法？

问题如下：

Beta Corp. invested $50,000 in a project at the beginning of this year. The project is expected to generate annual cash flows at $12,500 for five years. Assume the required rate of return is 6%, which of the following is most appropriate?

选项：

payback period is 4 years, discounted payback period is 4.14 years.

payback period is 4 years, discounted payback period is 4.72 years.

payback period is 4.86 years, discounted payback period is 4 years.

解释：

B is correct.

In year 4, the cumulative cash flows is 0, therefore payback period is 4. Discounted payback period is longer than payback period, calculated as 4+6686/9341=4.72 years.