You borrowed $ 18,000 for 8 years and agree to make total quarterly payments of $ 770. Each of these payments consists of interest for the just completed quarter and a deposit to a Sinking Fund. For the first 6 years, the lender receives 8% nominal rate convertible quarterly. For the remaining 2 years, the lender receives 12% nominal rate convertible quarterly. The Sinking Fund earns 6% nominal rate convertible quarterly. Find the amount by which the Sinking Fund is short of repaying the loan at the end of 8 years.