Facts Enterprises is trying to select the best investment from among four alternative independent projects presented by their respective firms. Each alternative involves an initial outlay of $80,000 and a 10% cost of capital. Management requires that all project investments should be recovered in 4 years. Their cash flows follow:

Year	Sun Ltd	Moon Ltd	Best Ltd	Pep Ltd
1	30,000	20,000	20,500	0
2	25,000	30,000	20,500	30,000
3	20,000	0	20,500	0
4	15,000	20,000	20,500	28,000
5	10,000	10,000	20,500	25,000
6	5,000	30,000	0	40,000

iii) Calculate the discounted payback period for the projects with positive NPVs.

iv) What does it mean for projects to be mutually exclusive? How should managers rank mutually exclusive projects?