JEE Mains · Maths · STD 11 - 6. permutation and combination
The number of ways, 5 boys and 4 girls can sit in a row so that either all the boys sit together or no two boys sit together, is ___________ -
- A 17284
- B 17265
- C 17280
- D 14785
Answer & Solution
Correct Answer
(C) 17280
Step-by-step Solution
Detailed explanation
A : number of ways that all boys sit together \(=5!\times 5!\) B : number of ways if no 2 boys sit together \(=4!\times 5\) ! \(\mathrm{A} \cap \mathrm{B}=\phi\) Required no. of ways \(=5!\times 5!+4!\times 5!=17280\)
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