Answer:
a. $750,000
Explanation:
We can compute the depletion expense by dividing investment by total available capacity of the coal mine. We charge the full investment as there is no salvage value.
Depletion expense = 15 / 20 = $0.75 million per million tons.
Total extracted coal = 1,000,000
so depletion expense for the first year = 1,000,000 * 0.75 = $750,000
We calculated depletion as we would any depreciation and charge it on activity basis which is the amount of coal extracted.
Hope that helps.