Three friends Atul, Bikram and Chotu started a business with initial investments in the ratio of 3 : 2 : 5. After 3 months, Atul further adds Rs. 20000 and Bikram adds Rs. 10000 further 3 months later.If after 1 year, the ratio of their profit sharing is 18 : 8 : 10 then what was Chotu’s initial investment?