Last Updated on May 6, 2023
GMAT OFFICIAL GUIDE DS
Solution:
We need to determine the value of n in the list: n, 15, 12, 9, 20.
Statement One Alone:
n > 12
Only knowing that n > 12 is not enough to determine the value of n. For example, n can be 13 or 14 (or some other number greater than 12). Statement one alone does not provide enough information to answer the question. We can eliminate answer choices A and D.
Statement Two Alone:
The median of the numbers in the list is 13.
We are given a list of 5 values: n, 15, 12, 9, and 20. Since we have 5 numbers in the list (an odd number of values), the median is equal to the middle value when the data are ordered from least to greatest. Using statement two, when the values are ordered from least to greatest, the list looks like the following:
9, 12, 13, 15, 20
Since 13 is not one of the four known values in the list, we see that 13 must be equal to n.
Answer: B
