Official Guide Explanation:
Data Sufficiency #81

Background

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Solution and Metadata

Question: 81
Page: 279
Difficulty: 4 (Moderately Easy)
Category 1: Arithmetic > Descriptive Statistics > other

Explanation: Statement (1) tells us nothing: Between the list of numbers and k < n, there's no way to find the value of n.

Statement (2) is also insufficient. Given a list of 5 (or any odd number of) numbers, the median must be one of the numbers in the set. Since the median of this list is 10 and 10 isn't one of the numbers listed, either k = 10 or n = 10. If we put the numbers in order, it looks like this:

6,(k/n),(k/n),12,17

Either k or n is the median--whichever is larger.

Taken together, the statements are sufficient. Since (1) tells us that n is larger than k, the order of the numbers is:

6,k,n,12,17

The middle number is the median, so n = 10. Choice (C) is correct.

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