Arun and Ajoy started a business jointly by investing ₹ 24,000 and ₹ 30,000 respectively at the begining of the year. But after a few months Arun invested ₹ 12,000 more. After a year the profit was ₹ 14,030 and Arun received the profit share of ₹ 7,130. Let us find after how many months did Arun invest more money in that business.​