EcoTech Solutions is analyzing two projects with the following net cash flows. The company's required rate of return on investments is 15%. (PV of $1, FV of $1, PVA of $1, and FVA of $1).

Year	Project Eco1	Project Eco2
0	$(450,000)	$(500,000)
1	$150,000	$140,000
2	$190,000	$180,000
Year	Project Eco1	Project Eco2
3	$230,000	$220,000
4	$270,000	$260,000

a. Calculate the payback period for each project. Which project is preferred based on the payback period?

b. Calculate the net present value for each project. Which project is preferred based on the net present value?