PSAT Math Multiple-Choice Question 833: Answer and Explanation

Question: 833

If an amusement park worker measures 3 riders as being 48 inches, 56 inches, and 40 inches tall and the margin of error of each of the worker's measurements is ±2 inches, what is the possible range of the sum of the riders' actual heights in inches?

• A. 48 ≤ total height ≤ 144
• B. 42 ≤ total height ≤ 150
• C. 138 ≤ total height ≤ 150
• D. 158 ≤ total height ≤ 180

Correct Answer: C

Explanation:

(C) Since there are three separate measurements that are each off by up to 2 units, you can determine the range of possible values by adding all the individual measurements together and then including a range of plus or minus 6:

48 + 56 + 40 = 144
144 + 6 = 150
144 - 6 = 138

Choice (C) shows the correct range.