Official Guide Explanation:
Data Sufficiency #101

Background

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Solution and Metadata

Question: 101
Page: 160
Difficulty: 4 (Moderately Easy)
Category 1: Arithmetic > Descriptive Statistics > Average

Explanation: If the average of 4 numbers is 50, the sum of the numbers is 200. That may be easier to work with than the average.

Statement (1) is insufficient: the numbers could be 49, 49, 51, and 51 (2 numbers greater than 50), or 1, 1, 1, and 197 (one number greater than 50). Statement (2) is also insufficient: the numbers could be 25, 25, 75, and 75 (two numbers greater than 50), or 25, 25, 25, and 125 (one number greater than 50).

Taken together, the statements are still insufficient. Both of the examples given for (2) also satisfy the requirement given in (1), so they can be used here. Since it's possible that one or two numbers is greater than 50, choice (E) is correct.

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