308 gallons of 7% and 77 gallons of 2% are needed to obtain the desired 385 gallons.
<h3><u>Combination</u></h3>
Since a dairy needs 385 gallons of milk containing 6% butterfat, to determine how many gallons each of milk containing 7% butterfat and milk containing 2% butterfat must be used to obtain the desired 385 gallons, the following calculation must be performed:
385 x 0.06 = 23.1
300 x 0.07 + 85 x 0.02 = 22.7
310 x 0.07 + 75 x 0.02 = 23.2
308 x 0.07 + 77 x 0.02 = 23.1
Therefore, 308 gallons of 7% and 77 gallons of 2% are needed to obtain the desired 385 gallons.
