(10) व्यक्तियों में (A) और (B) विशेष हैं। (5) व्यक्ति ऐसे चुनने हैं कि (A) और (B) में से ठीक एक चुना जाए। कुल चयन कितने हैं?
Among (10) persons, (A) and (B) are special. How many ways can (5) persons be chosen so that exactly one of (A) and (B) is selected?
Explanation opens after your attempt
Correct Answer
A. (140)
Concept
There are (2) ways to choose the special person and then (4) from the other (8), so \(2\binom{8}{4}=140\). Exactly one means two symmetric cases.
Why this answer is correct
The correct answer is A. (140). There are (2) ways to choose the special person and then (4) from the other (8), so \(2\binom{8}{4}=140\). Exactly one means two symmetric cases.
Exam Tip
विशेष व्यक्ति चुनने के (2) तरीके और बाकी (4) व्यक्ति (8) में से, इसलिए \(2\binom{8}{4}=140\)। ठीक एक का अर्थ है दो समान मामले।
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