"A firm is trying to decide whether to keep an item of construction equipment for another year. The firm has been using double-declining-balance (DDB) for book purposes, and this is the 5th year of ownership of the equipment, which cost $118,000 new. The useful life of the asset is 7 years and has a salvage value of $10,000. What is the book value of the equipment at the end of year 4?"