A and B invest Rs. 3000 and Rs. 4000 respectively in a business. After 6 months, A doubles his investment. What is the ratio in which A and B should share the profit at the end of one year?

Explanation

A's investment for the first 6 months is Rs. 3000 and for the next 6 months it becomes Rs. 6000. Therefore, A's total investment-time = 3000 × 6 + 6000 × 6 = 18000 + 36000 = 54000. B invests Rs. 4000 for the entire 12 months, so B's investment-time = 4000 × 12 = 48000. The profit ratio is proportional to investment-time, which is 54000 : 48000 = 9 : 8.