A firm is considering the following projects. Its opportunity cost of capital is 8%. a-1. What is the payback period on each project? (Do not round intermediate calculations. Round your answers to the nearest whole number.) a-2. What is the discounted payback period on each project? (Do not round intermediate calculations. Round your answers to 2 decimal places. If any of the projects does not pay back on a discounted basis, enter zero ("O").)