Question
Question: A subset P is selected from a set S containing n elements and elements of P are then replaced in S a...
A subset P is selected from a set S containing n elements and elements of P are then replaced in S and another subset Q is selected. The no. of ways can this be done. Such that P∩Q = φ
A
2n
B
4n
C
3n
D
n
Answer
3n
Explanation
Solution
For each element in S, there are 3 choices.
(1) Putting in P only
(2) Putting in Q only
(3) Not putting in P or Q.
∴No. of choices of n elements = 3n.