PSAT Math Multiple-Choice Question 725: Answer and Explanation

Question: 725

When Andrew does his homework, he always takes 10 minutes to set up his desk and get totally ready to begin. Once he starts working, he is able to complete 1 homework problem every 5 minutes. Assuming that Andrew studies for over 10 minutes, which of the following represents the total number of homework problems, p, Andrew is able to complete in m minutes?

• A. p = 5m + 10
• B. p = 5m - 1
• C.
• D.

Correct Answer: C

Explanation:

(C) Whenever Andrew starts a problem, he always takes the 10 minutes of time to set up. Then he completes 1 problem every 5 minutes of actual study. So the number of minutes he takes to do p problems is 10 + 5p . If you set up the equation for this, it is m = 10 + 5p . Solving for p gives the correct answer: