MNO Foods is considering investing in new equipment to boost production. The details for three machines are as follows. Assume all sales are on cash. The corporate income-tax rate is 31%. Interest on capital may be assumed to be 9%.

Particulars	Machine Q(Rs)	Machine R(Rs)	Machine S(Rs)
Initial investment	4,20,000	4,50,000	4,80,000
Estimated annual sales	5,50,000	5,80,000	6,00,000
Cost of production:
Direct material	60,000	65,000	70,000
Direct labour	55,000	60,000	65,000
Factory overhead	75,000	80,000	85,000
Administration cost	22,000	20,000	18,000
Selling & Distribution cost	12,000	14,000	16,000

The economic life of Machine Q is 3 years, Machine R is 5 years, and Machine S is 4 years. The scrap values are Rs.30,000, Rs.25,000, and Rs.35,000 respectively. You are required to find out the most profitable investment based on the payback period method.