The square box is considering two independent projects with an initial cost of $18,000 each. the cash inflows of project a are $3,000, $7,000, and $10,000 for years 1 to 3, respectively. the cash inflows for project b are $3,000, $7,000, and $15,000 for years 1 to 3, respectively. the required return is 12 percent and the required discounted payback period is 3 years. based on discounted payback, which project(s), if either, should be accepted?