<p>ehighmark2443, I got the exact same answers as you. And I am sure that Collegeboard intended for the short-run quantity to be constant. In the past (see past exams at AP Central) they have tested students on lump-sum subsidies and the scoring guidelines emphasize that quantity will not change. Since a lump-sum subsidy does not depend on quantity, what incentive do firms have to produce more?</p>