If U = {1,2,3,4,5,6,7,8}, A = {1,2,3,4}, and B = {3,4,5,6}, what is |𝒫((A ∩ B)′)|?
Answer and explanation
Correct answer: 64
First find the intersection: A ∩ B = {3,4}, which has 2 elements. The complement is taken relative to U, so (A ∩ B)′ = U − {3,4} = {1,2,5,6,7,8}. This complement has 6 elements. The number of subsets of any six-element set is 2^6 = 64, including the empty subset. Hence |𝒫((A ∩ B)′)| = 64, making option C correct.
Frequently asked questions
What is the correct answer to this question?
64
Why is this the correct answer?
First find the intersection: A ∩ B = {3,4}, which has 2 elements. The complement is taken relative to U, so (A ∩ B)′ = U − {3,4} = {1,2,5,6,7,8}. This complement has 6 elements. The number of subsets of any six-element set is 2^6 = 64, including the empty subset. Hence |𝒫((A ∩ B)′)| = 64, making option C correct.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Power Set and Subsets.