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प्रश्न
A candidate is required to answer 7 questions out of 12 questions which are divided into two groups, each containing 6 questions. He is not permitted to attempt more than 5 questions from either group. He can choose the seven questions in 650 ways.
विकल्प
True
False
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उत्तर
This statement is True.
Explanation:
The candidate may attempt in following manner
| Group A | 2 | 3 | 4 | 5 |
| Group B | 5 | 4 | 3 | 2 |
So, the number of attempts of 7 questions
= 6C2 × 6C5 + 6C3 × 6C4 + 6C4 × 6C3 + 6C5 × 6C2
= 2[6C2 × 6C5 + 6C3 × 6C4]
= 2 [15 × 6 + 20 × 15]
= 2[90 + 300]
= 2 × 390
= 780.
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