If U = {1,2,3,4,5,6,7,8,9}, A = {1,3,5,7,9}, and B = {2,3,5,8}, what is |P((A − B)′)|?
Answer and explanation
Correct answer: 64
First calculate the difference: A − B = {1,7,9}, because 3 and 5 belong to both A and B. The prime symbol means complement relative to U. Hence (A − B)′ = U − {1,7,9} = {2,3,4,5,6,8}, which has 6 elements. Its power set therefore has 2⁶ = 64 members. Thus option C is correct.
Frequently asked questions
What is the correct answer to this question?
64
Why is this the correct answer?
First calculate the difference: A − B = {1,7,9}, because 3 and 5 belong to both A and B. The prime symbol means complement relative to U. Hence (A − B)′ = U − {1,7,9} = {2,3,4,5,6,8}, which has 6 elements. Its power set therefore has 2⁶ = 64 members. Thus option C is correct.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Power Set and Subsets.