Louie made 8.1 liters of fruit punch using only grape juice and carbonated water. he used 4.2 liters of grape juice. the equation 4.2+c= 8.1 can be used to represent this situation, where c is the number of liters of carbonated water used. how many liters of carbonated water did louie use? a.)3.9 liters b.)4.1 liters c.)12.3 liters d.)16.5 liters