SAT Math Multiple Choice Practice Question 178: Answer and Explanation

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Question: 178

2. Which of the following is true for the set of numbers 13, 19, 20, 20, 22, 29, 42, 63?

I.median = mode

II.mean > median

III.mode < mean

A. I only
B. II only
C. I and III
D. II and III
E. none of the above

Correct Answer: D

Explanation:

D. The mode, if you remember, is the number that shows up most often, so in this case the mode is 20. The median is the middle number. Because there are two numbers in the middle, 20 and 22, the median is their average, or 21. Already you know that I is not true, so you can eliminate Choices (A) and (C). Now you need to determine the mean, also known as the average. To find the mean, add all the numbers together and divide by the number of numbers: (13 + 19 + 20 + 20 + 22 + 29 + 42 + 63) ÷ 8 = 228 ÷ 8 = 28.5. Now you know that II and III are both true, so the answer must be Choice D.

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