Ceradyne, Inc. , reported the following items on its December 31, 2011, balance sheet ($ in thousands):

property, plant and equipment .net = $428 562

Accumulated depreciation = 185186

1. Compute Ceradynes historical cost of property, plant, and equipment on December 31, 2011. 2. If Ceradyne uses a 12-year economic life for computing straight-line depreciation on most of its assets, are most of its assets more than or less than 5 years old? Explain how you can determine this.