ABC Manufacturing is considering two projects, Project X and Project Y. Both projects require an initial investment of GBP 30,000. The following are the expected cash inflows:

Year	Cash flows (Project X)	Cash flows (Project Y)
(Initial Investment)	(30,000)	(30,000)
1	10,000	15,000
2	10,000	10,000
3	5,000	15,000
4	5,000	10,000

a. Calculate the payback period for both projects.

b. Which project should ABC Manufacturing invest in if their payback period threshold is 3 years? Justify your answer.