Q. 175.0( 1 Vote )
Mark the correct alternative in the following:
If 
, then 
is equal to
A. 56
B. 120
C. 28
D. 91
Answer :
If set S has n elements, then C(n,k) is the number of ways of choosing k elements from S.
Thus, the number of subsets of S of all possible values is given by,
C(n,0) + C(n,1) + C(n,2) + . . . . . . . . . . + C(n,n) = 2n
Comparing the given equation with the above equation we get,
2n = 256
2n = 28
n = 8
2nC2 = 16C2
= 120
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