Could you please explain to me on how I eliminate land from PP&E, so I can finish my calculations below? I only included them for the purpose of why I need to remove land.

I'm supposed to use the company I selected (Apple Inc) to calculate:

Average total life span = Gross plant and equipment assets / Current year depreciation expense.

Average age = Accumulate depreciation / Current year depreciation expense.

Average remaining life = Net plant and equipment assets / Current year depreciation expense.