IBPS RRB Officer Prelims 14 Nov 2016 Shift 3 Paper

A and B both start a small business with an investment of Rs. 3500 and Rs. 4000 respectively. At the end of few months from the start of the business, A withdrew from the business completely and B remained for the years. If the annual profit was divided between A and B in the respective ratio of 7 : 12, then after how many months from the start of the business, did A leave the business?