If U is the set of all days of the week and A = {Monday, Wednesday, Friday}, how many days are in A′?
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Answer and explanation
Correct answer: 4
The universal set U contains seven days, while A contains three specified days. The complement A′ consists of the days in U that are not in A: Tuesday, Thursday, Saturday, and Sunday. Therefore, |A′| = |U| − |A| = 7 − 3 = 4. Thus option B is correct; three is the size of A, not its complement.
Frequently asked questions
What is the correct answer to this question?
4
Why is this the correct answer?
The universal set U contains seven days, while A contains three specified days. The complement A′ consists of the days in U that are not in A: Tuesday, Thursday, Saturday, and Sunday. Therefore, |A′| = |U| − |A| = 7 − 3 = 4. Thus option B is correct; three is the size of A, not its complement.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Complement of a Set and Its Properties.
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