A firm is considering the following projects:

Year	Project Z (₹)	Project AA (₹)
0	-15,000	-12,000
1	3,000	3,000
2	5,000	5,000
3	6,000	7,000
4	8,000	6,000

Requirements:

1. Determine the payback period for each project.
2. Select the project if the cutoff period is 3 years.
3. Calculate the discounted payback period using a 10% discount rate.
4. Assess which project fulfills a 2.5-year discounted payback criterion.

Evaluate the NPV for each project and recommend the preferable project.