posted by Scott .
You need 1/2 cup of sugar to make a three-layer cake. How much sugar would you need for a one-layer cake
1/3 * 1/2 = 1/6 cup
You need 1/3 as much
(1/2)/(3/1) = 1/2 x 1/3 = 1/6
As a sidenote, I can assure you that three layer cakes need a lot more sugar than this. I would add from 1 1/3 Cup to 1 1/2 cup, depending on the frosting planned. This is almost three times as much sugar as your math problem. Perhaps your teacher is watching her calories.