John Tupper, D.D.S., opened an incorporated dental practice called John Tupper Professional Dentistry Corporation on January 1, 2020. During the first month of operations the following selected transactions occurred: 1. 23 4. Performed services for patients who had dental plan insurance. At January 31, $800 of such services was earned but not yet billed to the insurance companies. Utility expenses incurred but not paid prior to January 31 totalled $460. Purchased dental equipment on January 1 for $68,000, paying $20,000 in cash and signing a $48,000, 3-year note payable (interest, at 6% is paid each December 31). The equipment is being depreciated using the straight-line method. Management expects it to have a useful life of 15 years and a residual value of $6,800. Interest has not been recorded for the month. Purchased a 1-year malpractice insurance policy on January 1 for $22,800. The cost of the insurance policy was debited to the Prepaid Insurance account when purchased on January 1. Purchased $1,750 of dental supplies (recorded as increase to Supplies). On January 31 determined that $400 of supplies were on hand. Prepare the adjusting entries required on January 31. (Credit account titles are automatically indented when the amount is entered. Do not indent manually. If no entry is required, select "No Entry" for the account titles and enter O for the amounts.) No. Date Account Titles and Explanation Jan. 1. 31 Debit Credit