Consider the question. Elmo has 3 times as many books as his sister, Laura. Laura has twice as many books as her brother, Stu. If Elmo has 24 books, how many books does Stu have?
 If the answer is '4'; explain the reasoning:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Laura has 24 / 3 = 8 books. Stu has 8 / 2 = 4 books.