Give the step-by-step reasoning process and then the final answer. Lizzie has half as many crayons as Bobbie. Bobbie has three times as many crayons as Billie. If Billie has 18 crayons, how many crayons does Lizzie have?
Bobbie has 18 * 3 = 54 crayons. Lizzie has 54 / 2 = 27 crayons.
The final answer: 27.