COMEDK · Maths · 20. Sets and Relations
\(\text { If } a \mathcal{N}=\{a x: x \in \mathcal{N}\} \text {, then } 3 \mathcal{N} \cap 7 \mathcal{N} \text { is }\)
- A \(10 \mathcal{N}\)
- B \(4 \mathcal{N}\)
- C \(21 \mathcal{N}\)
- D \(3 \mathcal{N}\)
Answer & Solution
Correct Answer
(C) \(21 \mathcal{N}\)
Step-by-step Solution
Detailed explanation
The set \(a\mathcal{N}\) is defined as the set of all multiples of \(a\) where \(a \in \mathbb{N}\) and \(\mathcal{N} = \{1, 2, 3, \dots\}\). The set \(3\mathcal{N}\) consists of all natural numbers that are multiples of \(3\), i.e.,…
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