A, B and C started a business with investments of 1,600/-, 2,100/- and 1,500/- respectively. After 8 months from the start of the business, B and C invested additional amounts in the ratio of 3 : 5 respectively. If the respective ratio between total annual profit and C’s share in the annual profit was 3 : 1, what was the additional amount invested by B after 8 months ?