Martinez Company owns a building that appears on its prior year-end balance sheet at its original $640,000 cost less $480,000 accumulated depreciation. The building is depreciated on a straight line bash assuming a 20 year life and no salvage value. During the first week in January of the current calendar year, major structural repairs are completed on the building at a $164,000 cost. The repairs extend its useful life for 5 years beyond the 20 years originally estimated Determine the building's age (plant asset age) as of the prior year end balance sheet date