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If nCr+nC(r+1)=(n+1)Cx then x=?...

If `nC_r`+`nC_(r+1)`=`(n+1)C_x` then x=?

A

a) r

B

b) r-1

C

c) n

D

d) r+1

Text Solution

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The correct Answer is:
D
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PATHFINDER-PERMUTATION AND COMBINATIONS-QUESTION BANK
  1. The result of ^(n-1)Cr+^(n-1)C(r-1)=

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  2. If ^nCp= ^nCq and pneq then (n-p) is

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  3. If nCr+nC(r+1)=(n+1)Cx then x=?

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  4. ^11C8+^11C9= which of the following

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  5. If 16Cr=^16C(2r+1) then the value of r will be

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  6. If ^9P5=x^9P3 then the value of x will be

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  7. If ^nPr=^nP(r+1) and ^nCr=^nC(r-1) then the values of n,r are

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  8. The value of sum(r=1)^n (^nPr)/(r!) is

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  9. Let Tn denote of the number of triangles which can be formed using the...

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  10. The number of parallelograms that can be formed from a set of four par...

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  11. A polygon has 44 diagonals the number of sides of the polygon is

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  12. In a room each person present shakes hand with the other . If the tota...

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  13. The value of : ^15C1 +^15C3 + ^15C5+…..+ ^15C15 is

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  14. The number of 10 digit numbers formed by using the digits 1&2 is

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  15. The maximum number of trials to open n locks by n keys is 105. Then n...

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  16. The number of circles that can be drawn out of 10 points of which 7 ar...

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  17. The number of different 6-digit numbers that can be formed using the t...

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  18. The number of ways in which 6 different balls can be put in two boxes ...

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  19. If 7 points out of 12 are in same st. line the number of triangles for...

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  20. The total number of 9 digit numbers which have all different digit is

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