Consider the following cash flows: What is the NPV at a discount rate of zero percent? (Do not intermediate calculations and round your answer to the nearest whole number, e.g., 32.) Net present value $ What is the NPV at a discount rate of 8 percent? (Do not intermediate calculations and round your answer to 2 decimal places, e.g., 32.16.) Net present value $ What is the NPV at a discount rate of 18 percent? (A negative answer should be indicated by a minus sign. Do not round intermediate calculations and round your answer to 2 decimal places, e.g., 32.16.) Net present value $ What is the NPV at a discount rate of 28 percent? (A negative answer should be indicated by a minus sign. Do not round intermediate calculations and round you answer to 2 decimal places, e.g., 32.16.) Net present value $