The set A contains the prime numbers between 20 and 30. Which option correctly describes A?
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Answer and explanation
Correct answer: A = {23, 29}, and it is finite
The integers strictly between 20 and 30 are 21 through 29. Among them, 23 and 29 are prime: each has exactly two positive divisors, 1 and itself. The numbers 21 and 27 are composite, so they cannot be included. Thus A = {23, 29}, which has two elements and is therefore finite.
Frequently asked questions
What is the correct answer to this question?
A = {23, 29}, and it is finite
Why is this the correct answer?
The integers strictly between 20 and 30 are 21 through 29. Among them, 23 and 29 are prime: each has exactly two positive divisors, 1 and itself. The numbers 21 and 27 are composite, so they cannot be included. Thus A = {23, 29}, which has two elements and is therefore finite.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: The Empty Set, Finite and Infinite Sets, Equal Sets.
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