DEF Inc. plans to invest in a machinery costing $250,000. The machinery is expected to yield the following cash flows over its useful life of 6 years:

Year	Cash Flow
1	$70,000
2	$60,000
3	$50,000
4	$40,000
5	$30,000
6	$20,000

The machine has no salvage value, and the company uses straight-line depreciation. The corporate tax rate is 28%. Required:

a. Calculate the Payback Period and ARR
 b. Calculate NPV and PI, assuming a 10% discount rate
 c. Compute the IRR
 d. Determine the impact on NPV if the discount rate increases by 2%