Down Deep Mining Co$.$ acquired mineral rights for $$27,000,000.$ The mineral deposit is estimated at $30,000,000$ tons. During the current year, $6,000,000$ tons were mined and sold.

a$.$ Determine the depletion rate. If required, round your answer to two decimal places. per ton

b$.$ Determine the amount of depletion expense for the current year.

c$.$ Journalize the adjusting entry on December $31$ to recognize the depletion expense. If an amount box does not require an entry, leave it blank.

Dec. $31.$