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If 2lerlen show that ^nCr +2 ^nC(r-1) +^...

If `2lerlen` show that `^nC_r +2 ^nC_(r-1) +^nC_(r-2)=^(n+2)C_r`

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PATHFINDER-PERMUTATION AND COMBINATIONS-QUESTION BANK
  1. Find the value of k if ^(k^2-2k)C9 = ^(k^2-2k)C6

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  2. If ^nPr=336 and ^nCr=56 then find n and r.

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  3. If 2lerlen show that ^nCr +2 ^nC(r-1) +^nC(r-2)=^(n+2)Cr

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  4. Find the number of different factors of 3528 which are greater than 1 ...

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  5. In a plane there are 10 points out of which no three are collinear exc...

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  6. In a plane there are 10 points out of which no three are collinear exc...

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  7. In how many ways can be 9 man be selected from 15 men so as always to ...

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  8. In how many ways can be 9 man be selected from 15 men so as always to ...

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  9. How many each consisting of five different letters can be formed by ta...

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  10. In how many ways can six students be seated in a line so that two part...

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  11. Find the value of x if ^(4x-2)P2=6

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  12. In how many ways can 5 boys and 3 girls be arranged so that no two gir...

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  13. Find the number of different arrangements with the letters of the word...

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  14. How many numbers of 4 digit greater than 6000 can be formed with the d...

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  15. A book store has 2 different books each having 3 volumes and 3 other d...

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  16. From 5 oranges, 4 mangoes and 2 apples, how many different selection o...

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  17. For a certain class, in how many different routines can the 5 differen...

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  18. An examine is required to answer 6 questions out of 12 questions which...

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  19. Find the number of permutations of the letters of the words 'FORECAST'...

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  20. How many triangles can be formed by joining the angular points of a de...

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