Mr. Pitkin bought a farm and promised to pay $6850 in 7 years with 8% simple interest and $11575 in 15 years with 10.75% simple interest. Later, Mr. Pitkin met with the lender requesting to pay $6900 at the end of 5 years and to make a final payment at the end of 12 years. Based on a simple interest rate of 15%, determine the amount required to settle the debt at the end of 12 years.