Answer:
Project Y Project Z
(6 years) (5 years)
investment: -$345,000 -$345,000
cash flows:
net income after taxes $50,840 $32,984
+ depreciation expense $57,500 $69,000
net cash flow per year = $108,340 $101,984
payback period:
investment / NCF = 3.18 years 3.38 years
accounting rate or return:
net income / investment = 14.74% 9.56%
net present value:
NCFs discounted at 6% = $187,743 $84,594
Project Y lasts for 6 years, while project Z lasts for only 5 years, that is the reason why there NPVs are so different.