A taxi driver invested an amount of Rs. 20,000 at a simple interest of 9% per annum and another amount at a simple interest of 15% per annum. The total interest earned at the end of one year is equal to 12% of the total amount invested. Find the total amount invested.
1
Rs. 40,000
2
Rs. 28,000
3
Rs. 30,000
4
Rs. 35,000