Give the step-by-step reasoning process and then the final answer. Every week of last month Paul tried out a new cake recipe. The first week, he followed a cake recipe that called for 24 cups of sugar. Each week after that, he reduced the amount of sugar by half. How much sugar did he use for the cake on the fourth week?
On the 2nd week, Paul halved the first week's sugar, therefore he used 24 / 2 = 12 cups. The third week, Paul used 12 / 2 = 6 cups. The fourth week, he used 6 / 2 = 3 cups.
The final answer: 3.