(1) If the median of S is 0, we know:
*0 is the middle value of the set
*Since the set is sequential, 0 is also the third value in the set (since there are 5 values)
*Since the set is sequential, set S must be {-2,-1,0,1,2}
Of course, this tells us nothing about set T, so (1) is Insufficient.
(2) If the sum of each set is equal,
Let the first value of set S = s
Let the first value of set T = t
Since they are both sequential,
S = {s,s+1,s+2,s+3,s+4}
T = {t,t+1,t+2,t+3,t+4,t+5,t+6}
Therefore, sum of S = sum of T can be stated as...
s+s+1+s+2+s+3+s+4 = t+t+1+t+2+t+3+t+4+t+5+t+6
5s + 10 = 7t + 21
Because we don't know any value in either set, we cannot solve this, so (2) is insufficient.
Combining (1) and (2)...
From (1), we know the sum of A as
Sum A = (-2) +(-1) + 0 + 1 + 2 = 0.
From (2), we know that the sum of A is equal to the sum of T (which we showed as 7t + 21). So,
Sum A = Sum T
0 = 7t + 21
-7t = 21
t = -3
With -3 as its first value, set T is {-3,-2,-1,0,1,2,3}. This median is 0. So, we can determine whether or not the medians are equal.
Both together are sufficient. C.
