You are a restaurant manager and are responsible for ordering ingredients for the restaurant at supplier number one you can purchase 20 gallons of milk for $70 at supplier number two you can purchase 50 quarts of milk for $33.50 at supplier number three you can purchase 15 gallons for $48.75 and receive a course free which is the best deal

So basically you have 20 gal for 70 dollars 12.5 gal for 33.50 or 15 gal for 48.75. So you would need to find how much you spend per gallon divide total money by total gal. So for 15 gal you pay 3.25 per gal, for 12 gal you pay 2.79 per gal and for 20 gal you pay 3.5 per gal. Then I would find out how much I would pay each for 1 specific amount; so for 12 gal from each deal Deal A = 3.50(12)=42, Deal B 2.79(12)=33.50, Deal C 3.25(12)=39.
 So the best deal would be Deal C because it would initially come out cheaper and comes with a free meal.