What is the roster form of K₁ = {x : x ∈ ℕ, x is divisible by 7, and 30 < x < 60}?
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Answer and explanation
Correct answer: K₁ = {35, 42, 49, 56}
The multiples of 7 around the required interval are 28, 35, 42, 49, 56, and 63. The strict inequalities 30 < x < 60 exclude 28 and 63, as well as the endpoints 30 and 60 if they were multiples. The remaining values are 35, 42, 49, and 56. Therefore, option A gives the complete roster form.
Frequently asked questions
What is the correct answer to this question?
K₁ = {35, 42, 49, 56}
Why is this the correct answer?
The multiples of 7 around the required interval are 28, 35, 42, 49, 56, and 63. The strict inequalities 30 < x < 60 exclude 28 and 63, as well as the endpoints 30 and 60 if they were multiples. The remaining values are 35, 42, 49, and 56. Therefore, option A gives the complete roster form.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Sets and their representations.
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