If we arrange the set in ascending order -
_ 3 _ 5 _ 6 _ 10 _ 12 _
x can take any of places indicated by dash.
Another observation - the set consists of even number of terms, so the median would be the average of the middle two terms.
Statement 1 Case 1Lets assume that x does not occupy the first or the last position. Therefore the available positions that x can take -
3 _ 5 _ 6 _ 10 _ 12
Range = 10 - 3 = 9
Median = 7
For median to be 7
x = 8
Case 2Lets assume that x occupies the first position
Range = 12 - x
Median = 5.5
12 - x = 5.5 + 2
x = 4.5
This is not possible, hence disregard this case.Case 3Lets assume that x occupies the last position
Range = x - 3
Median = 8
12 - x = 8 + 2
x = 13
Hence we have two possible values of X.
Therefore statement 1 is not sufficient.
Statement 2Median is 7
Now 7 is not present in the set. The possible position of the x can be between 6 and 10 (because we saw that median is 8 when 6 & 10 are in the center, so for median 7, x has to be less than 10 and greater than 6)
For median to be 7, x = 8
Hence sufficient.
IMO - B