An investor took out a loan of 115,000 at 10% compounded quarterly, to be repaid over 12 years with quarterly payments of 4,140.69 at the end of each quarter. After 16 payments, the interest rate dropped to 8% compounded quarterly. The new quarterly payment dropped to 3,855.01. After 32 payments in total, the interest rate on the loan increased to 9% compounded quarterly. The investor decided to make an additional payment of X at the time of payment number 32. After the additional payment was made, the new quarterly payment was calculated to be 3170.09, payable for 4 more years. Determine X. [6.a #05] 5,270 10,140 6.490 8.920 7,710