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If ""^(56)P(r+6) : ""^(54)P(r+3)= 30800...

If ` ""^(56)P_(r+6) : ""^(54)P_(r+3)= 30800, ` then r is

A

39

B

41

C

28

D

43

Text Solution

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The correct Answer is:
B
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If ^(56)P_(r+6):^(54)P_(r+3)=30800 :1, find r .

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AAKASH INSTITUTE ENGLISH-PERMUTATIONS AND COMBINATIONS -Assignment Section A Objective type questions (One option is correct )
  1. The value of n, if ""^(n)P(5) = 20.""^(n)P(3) , is

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  2. In how many ways the letters of the word RAINBOW be arranged ?

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  3. If ""^(56)P(r+6) : ""^(54)P(r+3)= 30800, then r is

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  4. How many numbers are greater than 50000 can be formed with the digits ...

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  5. In how many ways can 10 soldiers stand in two rows having 5 soldiers i...

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  6. In how many ways 6 students and 4 teachers be arranged in a row so tha...

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  7. If ""^(n)C(x) = 56 and ""^(n)P(x) = 336 , then n is equal to

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  8. How many arrangements can be made out of the letters of the word COMMI...

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  9. How many different words can be made with the letter of the wor NAINIT...

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  10. How many numbers greater than a million can be formed with the digits ...

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  11. How many different signals cab be given using any number of flags from...

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  12. In how many ways can a committee of 4 men and 3 women be appointed fro...

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  13. In how many ways 7 members forming a committee out of 11 be selected s...

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  14. ""^(15)C(9)-""^(15)C(6)+""^(15)C(7)-^(15)C(8) equals to

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  15. The number of permutation of n different objects, taken r at a line, w...

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  16. The number of words which can be formed out of the letters of the word...

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  17. about to only mathematics

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  18. The number of ways in which three girls and ten boys can be seated in ...

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  19. IN a meeting everyone had shaken hands with everyone else, it was foun...

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  20. Number of different striaght lines that cn be formed by joining 12 dif...

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