The tax represents an added cost to producers and so results in a decrease in supply. You should draw a new supply curve that lies to the left of the original supply curve (above the original supply curve by the amount of the tax). The new equilibrium price will be $6 and, because demand is perfectly inelastic, the same quantity of 5 pounds will be sold. The total revenue from the tax is $2 per pound times 5 pounds or $10, shown as the rectangle whose height is from $4 to $6 and whose length is 5. For further review, go to Chapter 7; Section: The Economics of Taxes: A Preliminary View.