Food a contains 150 calories in 3/4 of a serving. food b contains 250 calories in 2/3 of a serving. which food has fewer calories per serving?

Food A has fewer calories per serving.

I found this by taking the first food (A) and dividing 150 by 3. This gave me 50, which I added onto 150 to give me my 4/4 of a serving (200 calories). 

With food B, I did the same process. I took 250/2 and added that to the original amount to get the final third of the serving, which resulted in food B being 375 calories.

Think of it as five or above give it a shove. change the 5 or above to the right to a zero and add one to the number on the left.