PSAT Math Multiple-Choice Question 763: Answer and Explanation

Question: 763

A typist has already typed 3,500 words of a document. How many total words, W(t), of the document will he have typed if he can type 70 words per minute and types for an additional t minutes?

• A. W(t) = 3,500t
• B. W(t) = 70t -3,500
• C. W(t) = 3,500t + 70
• D. W(t) = 3,500 + 70t

Correct Answer: D

Explanation:

(D) The typist has already typed 3,500 words, so this will be a constant in the expression. The typist types 70 words per minute. So if he types for t minutes, he will type 70t more words. Therefore, the total number of words typed, W(t), is given by the following ­expression:
W(t) = 3,500 + 70t
Choice (D) is correct.