YZA Ltd is considering purchasing a new machine to enhance production capacity. Three machines are under review. The details of estimated yearly expenditure and sales are provided below. All sales are on cash basis. Corporate income-tax rate is 31%. Interest on capital may be assumed to be 8%.

Particulars	Machine X (Rs)	Machine Y (Rs)	Machine Z (Rs)
Initial investment	4,00,000	4,25,000	4,50,000
Estimated annual sales	6,50,000	7,00,000	6,75,000
Cost of production:
Direct material	58,000	60,000	59,000
Direct labour	68,000	70,000	69,000
Factory overhead	78,000	80,000	79,000
Administration cost	27,000	28,000	28,000
Selling & Distribution cost	19,000	20,000	19,000

The economic life of machine X is 3 years, while it is 4 years for the other two. The scrap values are Rs. 55,000, Rs. 60,000 and Rs. 65,000 respectively. Find out the most profitable investment based on the payback period method.