Aman, Baman and Chaman started a business with investments of 10000, 1500 and 2000 respectively. After 9 months from start of the business , Baman and Chaman invested additional amounts in the ratio of 2: 1 respectively. If the ratio between total annual profit and Chaman’s share in the annual profit was 4:1, what was the additional amount invested by Baman after 9 months .