Arun and Ajoy started a business jointly by investing ₹ 24000 and ₹ 30000 respectively at the beginning of the year. But after a few months Arun invested ₹ 12000 more. After a year, the profit was ₹ 14030 and Arun received the profit share of ₹ 7130. Let us find after how months did does Arun invest money in that business.