The function ????=(????)=4???? tells how many quarts of a liquid are contained in ???? gallons of a liquid. (a) The inverse function ????−1(????) of ????(????) exists. Evaluate ????−1(28). (b) David owns a dairy farm. The function (????)=3???? tells how much money, in dollars, David charges for ???? quarts of milk. Give the formula for (????(????)). (c) Evaluate (????(4)). Interpret your answer in a complete sentence with units.