Answer:
Yes. (See below for explanation.)
Step-by-step explanation:
The number of servings is found by dividing the quantity available by the size of a serving. The quantity of punch is the sum of the quantities of the juices that go into the punch. The serving size of 3/4 cup is the same as 6 ounces, since a cup is 8 ounces. (3/4 × 8 oz = 6 oz)
The quantity available is (64 oz + 28 oz + 76 oz). The serving size is 6 oz. Since the units of numerator and denominator are the same, they cancel, leaving ...
... number of servings = (quantity available)/(serving size)
... = (64 +28 +76)/6 . . . . as shown in the problem statement
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It might not be obvious that the above ratio gives the number of servings. However, if you look at the real units, you see how it happens.