Zack, a small business owner, is thinking about investing $160,000 into a new project with an estimated life of 8 years. Because of low interest rates, he is earning virtually no return on his cash savings right now.

After making the investment, Zack will earn an extra 30% in revenues from his customers (his revenues totaled $70,000 last year). He will also save 10% on employee salaries, which are currently $6,000 monthly. However, he will incur an extra $4,000 a year in operating costs. What is Zack's cash payback period? Should he make the investment