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nCr+2. nC(r-1)+nC(r-2)=...

`nC_r+2. nC_(r-1)+nC_(r-2)=`

A

`n+1C_r`

B

`nC_(r+1)`

C

`n-1C_(r-1)`

D

`n+2C_r`

Text Solution

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The correct Answer is:
D
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HIMALAYA PUBLICATION-PERMUTATION AND COMBINATIONS-Question Bank
  1. If ""^nCr-84,""^nC(r-1)=36 and ""^nC(r+1)=126 , then n equals :

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  2. The value of sum(r=1)^(n)(nP(r))/(r!)=

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  3. nCr+2. nC(r-1)+nC(r-2)=

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  18. The number of four digit even numbers that can be formed using 0,1,2,3...

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  19. How many four digit numbers can be formed using digits 1,2,3,4,5 such ...

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