\(यदि (U={1,2,\ldots,27}), (A={x:x\) 3 का गुणज है\(}) और (B={x:x\) 9 का गुणज है\(}), तो (A'\cup B) में कितने अवयव हैं\)?
\(If (U={1,2,\ldots,27}), (A={x:x\) is a multiple of \(3}) and (B={x:x\) is a multiple of \(9}), how many elements are in (A'\cup B)\)?
Explanation opens after your attempt
Correct Answer
D. (21)
Concept
(A') has (27-9=18) elements and \(B\subseteq A\), so \(A'\cap B=\varnothing\). (B) has (3) elements, hence the total is (18+3=21).
Why this answer is correct
The correct answer is D. (21). (A') has (27-9=18) elements and \(B\subseteq A\), so \(A'\cap B=\varnothing\). (B) has (3) elements, hence the total is (18+3=21).
Exam Tip
(A') में (27-9=18) अवयव हैं और \(B\subseteq A\), इसलिए \(A'\cap B=\varnothing\)। (B) में (3) अवयव हैं, अतः कुल (18+3=21) है।
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