Aanya started a business by investing some money, and Manya invested Rs. 3,500 more than Aanya did. Aanya remained in business for 6 months, and Manya remained in business for 2 months more than Aanya. Out of the total profit of Rs. 18,000, Manya got Rs. 3,000 more than Aanya. Find the capital invested by Aanya.