1Yes Correct Debotosh
2) Given a subset X = {x1 , x2 , x3, ..............., x n } a subset P of X is formed and set is reconstructed by replacing the elements of P into X and then another subset Q of X is formed. Find the total no. of pair of subsets P and Q where
(i) P ∩ Q = null set
(ii) P ∩ Q contains exactly R elements
[where ∩ implies intersection of two sets]
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4 Answers
19ans 1> 3n.....there are three places ,after the reconstruction, in which each of the (n) elements can go !
62The second one is
nCr 3n-r
Think of the logic after seeing the answer