For the last $10$ years, Am$-$Mex Coal has used the cost depletion

factor of $$2500$ per $100$ tons to write off the investment of $$35$ million

in its Pennsylvania anthracite coal mine. Depletion thus far totals $$24\mathrm{.}8$

million. A new study to appraise mine reserves indicates that no more

than $800,000$ tons of salable coal remains. If estimated gross income is

expected to be $$8\mathrm{.}50$ million on a production level of $72,000$ tons,

determine next year$$s $($a$)$ cost$,$ and $($b$)$ percentage depletion amounts.

The percentage depletion allowance is $10\%.$