An investment project has annual cash inflows of $3,900, $4,800, $6,000, and $5,200, and a discount rate of 15 percent. What is the discounted payback period for these cash flows if the initial cost is $6,600?What is the discounted payback period for these cash flows if the initial cost is $8,700? What is the discounted payback period for these cash flows if the initial cost is $11,700?