Quick Print Press borrowed $20,000 from the Provincial Bank on May 25 at 7.5% and secured the loan by signing a promissory note subject to a variable rate of interest. Quick Print made partial payments of $5,000 on July 10 and $8,000 on September 15. The rate of interest was increased to 8% effective August 1 and to 8.5% effective October 1. What payment must Quick Print make on October 31 if, under the terms of the loan agreement, any interest accrued as of October 31 is to be paid on October 31?