Hi nahid078,

In this DS question, we're asked for the median of a set of 9 numbers (the 8 values listed and N). This question is perfect for TESTing Values.

To find the median of a group of numbers, we first must put those numbers in order from least to greatest. Since we have a variable in our set, we need to know more about N to establish the median of this group. Once the numbers are in order, the median will be the 5th value.

Fact 1: 11 < N < 22

Here we have a range of values for N.

If N = 12, then the 5th value = 12
If N = 13, then the 5th value = 13
With the given information, we know that N will be the median, but we don't know what N actually is.
Fact 1 is INSUFFICIENT

Fact 2: The set has 2 modes: 11 and 22

'Mode" means "most frequent number"; since the modes are 11 and 22, we know that N CANNOT be 1, 10, 11, 22, 35, or 47. In any of those situations, we either would have another mode or just the 11 or 22 would be the mode. The possibilities from Fact 1 fit this Fact as well.

The median could be 12 or 13.
Fact 2 is INSUFFICIENT

Combined, we have at least two different answers: 12 and 13; there's still no way to figure out the median.
Combined, INSUFFICIENT

Final Answer: E

GMAT assassins aren't born, they're made,
Rich