Final answer:
The unit rate in number of cups per serving is 3/4 cup.
Step-by-step explanation:
To find the unit rate in number of cups per serving, we need to divide the number of cups by the number of servings. In this case, Don ate 1/2 cup of vegetables, which was 2/3 of a serving. To find the unit rate, we divide 1/2 by 2/3. We can simplify this division by multiplying the numerator and denominator of 1/2 by the reciprocal of 2/3, which is 3/2. So, 1/2 ÷ 2/3 = 1/2 × 3/2 = 3/4. Therefore, the unit rate is 3/4 cup per serving.