"Showing both acquisition cost and accumulated depreciation amounts separately provides a rough indication of the relative age of the firm's long-lived assets."

a. Assume that the Dickens Company acquired an asset several years ago with a depreciable cost of $\$ 100,000$ and no salvage value. Accumulated depreciation as of December 31, recorded on a straight-line basis, is $\$ 60,000$. The depreciation charge for the year is $\$ 10,000$. What is the asset's total depreciable life? How old is the asset?

b. Assume straight-line depreciation. Devise a formula that, given the depreciation charge for the year and the asset's accumulated depreciation, you can use to estimate the age of the asset.