Hi Joy Shaha,

To start, this question should have been posted in the DS forum. That having been said, this is a relatively straight-forward prompt as long as you understand that statistical concepts involved.

Set 1: {2, 8, 10, 13]
Set 2: {2, 3, 11, 13.....X}

We're asked if the MEDIAN of Set 1 is equal to the MEDIAN of Set 2. This is a YES/NO question.

Since Set 1 has 4 terms, the median will be the average of the two "middle terms" - so the median of Set 1 is 9. Set 2 includes 5 terms, so the median number will the third number (once the 5 terms are listed from least to greatest) - the value of X will dictate what the median is. IF X=9, then the answer to the question is YES. IF X equals any OTHER value, then the answer to the question is NO.

1) 8 < X < 10

IF... X = 9, then the answer to the question is YES.
IF... X = 9.5, then the answer to the question is NO.
Fact 1 is INSUFFICIENT

2) The sum of numbers in Set 2 is 38

With this Fact, we can create the equation.... 2+3+11+13+X = 38. Thus, X = 9 and the answer to the question is ALWAYS YES.
Fact 2 is SUFFICIENT

Final Answer: B

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