If the containers are of equal size they must contain equal quantities. The sum of the quantities is 42+18=60 gallons, so each container must contain 30 gallons. If the proportions of the juices are to be kept the same, half the orange juice and half the cranberry juice must be in each container: 21 gallons of orange and 9 gallons of cranberry. Or 30 gallons of orange could fill one container, while the remaining 12 gallons of orange and all 18 gallons of cranberry would fill the other container.