Your goal is $660, but you already sell 25 tickets for $6 each so it is 25×6=150, which is $150. Now get 660-150=510, which means you need $510 more. Then divided 510 by 6 to solve for how many ticket you need to sell, which is equal 85 tickets. So 85 tickets must be sold at $6 apiece in order to make a profit.
