this is my question.

35. The corner gas station sells cigarettes, facing a linear downward sloping demand curve. To maximize revenue, the manager set the price equal to 14 dollars and sold a quantity of 40 packs per day on average. But to discourage smoking, the government just set a per-pack tax of 2 dollars, to be paid by the buyer. Now, to maximize revenue, the manager will reduce quantity by [ Answer35 ] packs per day on average. (Assume cigarettes are perfectly divisible.)