On January 1, 2016, the Hack Partnership was formed. Bill Barns acquired a 20 percent interest in the partnership by contributing a computer system that had an adjusted basis to him of $15,000, and was subject to a $5,000 liability. During the year, the partnership paid off the entire $5,000 liability. The partnership reported ordinary income of $75,000 on its 2016 partnership return. What is the amount of Bill's basis in the partnership on December 31, 2016?