PSAT Math Multiple-Choice Question 828: Answer and Explanation

Question: 828

A librarian works at a constant pace, simultaneously shelving exactly 200 books in an hour and exactly 20 movies in an hour, and shelving only books and movies. If the librarian works for a total of T hours, which expression shows the total number of items (books and movies) that the librarian shelves during that time?

• A. 220T
• B. 20T + 200
• C. 220T + 440
• D. 200T - 20

Correct Answer: A

Explanation:

(A) For each hour the librarian works, he or she shelves a total of 220 items. Therefore, the total number of items shelved during T hours is 220 × T. The other answer choices have constants either added or subtracted to the term multiplied by T. These answer choices would illogically mean that the librarian could shelve or remove items without spending any time at all doing so.