$9.$ A refinery processes $50,000$ barrels of crude oil with an API gravity of $30.$ If the yield of gasoline is $40\%,$ how many barrels of gasoline are produced?

$10.$ In a catalytic cracking process, $20,000$ barrels of heavy oil are processed to yield $15,000$ barrels of gasoline. What is the conversion efficiency of the process?

$11.$ If a hydrocracking unit processes $30,000$ barrels of heavy oil and converts $80\%$ of it into lighter products, how many barrels of heavy oil remain unconverted?

$12.$ A reforming unit processes $25,000$ barrels of naphtha and produces $17,500$ barrels of high$-$octane gasoline. What is the yield of gasoline?