Where R is the median between Q and L:
From my understanding of a triangle's centroid, it divides an angle bisector into parts of 2/3 and 1/3. In the given problem, these divisions are NS and SR. Therefore, twice SR would be equal to NS. From here, we can get the value of X, to solve for SR.
NS = 2SR
(x + 10) = 2(x + 3)
x + 10 = 2x + 6
x = 4
Therefore, SR = (x + 3) = 7