Explanation:
Food A:
\frac{150}{\frac{3}{4}}=150 \times \frac{4}{3} = 50 \times 4=200
The unit rate is 200 calories per serving.
Food B:
\frac{250}{\frac{2}{3}}=250 \times \frac{3}{2}=125 \times 3=375
The unit rate is 375 calories per serving.
Food A has fewer calories per serving.