On January 1, 2017, Betty DeRose, Inc. purchased equipment for $70,000. The equipment was assigned an estimated life of 12 years and a salvage value of $13,000. On January 1, 2022, Betty DeRose decided the life of the equipment should be changed from 12 to 18 years with a salvage value of $4,000 at the end of the 18 years. Betty DeRose uses the straight-line method to depreciate its assets. Calculate the book value of the equipment at December 31, 2027.