Math, asked by Anonymous, 11 months ago

Answer this
Hint: Permutation and Combination​

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Answers

Answered by naveen1925
1

I hope it can helps you...

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naveen1925: aap class 11th se ho
Anonymous: Thanks can you give me the formula for this?
naveen1925: ^nCr = nCn-r
naveen1925: thanks this is my first brainlist answer
shadowsabers03: Great. Congratulations!!!
naveen1925: thanks
Anonymous: Thats why only i marked your answer as brainliest ✌️
shadowsabers03: Haha, welcome.
naveen1925: hmm
Answered by shadowsabers03
1

\large \textit{According to\ \ $\ ^n\!C_r\ = \ ^n\!C_{n-r}$} \\ \\ \\ ^{18}C_r \ = \ ^{18}C_{18-r} \ = \ ^{18}C_{r+2} \\ \\ \\ 18-r=r+2 \\ \\ r+r=18-2 \\ \\ 2r=16 \\ \\ r=8

\Large \textit{Now let's find $\ ^r\!C_5$. }

\displaystyle ^r\!C_5 \ = \ ^8\!C_5 \ = \ \frac{8!}{5! \times 3!} \ = \ \frac{8 \times 7 \times 6 \times 5!}{5! \times 6} \ = \ 8 \times 7 \ = \ \bold{56}

\LARGE \textbf{Thus the answer is 56.}


Anonymous: Thanks a lot.
shadowsabers03: Welcome. :-))
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