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If rgtpgtq, the number of different sele...

If `rgtpgtq`, the number of different selections of `p+q` things taking r at a time, where p things are identical and q other things are identical, is

A

`p+q-r`

B

`p+q-r+1`

C

`r-p-q+1`

D

none of these

Text Solution

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The correct Answer is:
B
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OBJECTIVE RD SHARMA ENGLISH-PERMUTATIONS AND COMBINATIONS-Exercise
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  2. ""sum(r=1)^(4)""^(21-r)C(4)+ 17C(5), is

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  3. Given that .^(n)C(n-r)+3^(n)C(n-r+1)+3. .^(n)C(n-r+2)+.^(n)C(n-r+3)=...

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  4. If n is even and ""^(n)C(0)lt""^(n)C(1) lt ""^(n)C(2) lt ....lt ""^(...

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  5. Find the number of ways in which one can post 5 letters in 7letter ...

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  6. What is the total number of 2xx2 matrices with each entry 0 or 1...

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  7. Three dice are rolled. Find the number of possible outcomes in which a...

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  8. The numbers of four different digits number that can be formed from th...

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  9. If m and n are positive integers more than or equal to 2, mgtn, then (...

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  10. Find the number of integers which lie between 1 and 10^6 and which hav...

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  11. A man invites a party to (m+n) friends to dinner and places m at one r...

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  12. The number of ways of arranging m positive and n(lt m+1) negative si...

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  13. Out of 10 consonants four vowels, the number of words that can be form...

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  14. Four couples (husband and wife) decide to form a committee of four mem...

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  15. N a certain test, there are n question. In the test, 2^(n-i) students ...

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  16. The number of nine nonzero digits such that all the digits in the f...

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  17. The number of ways in which 20 different pearls of two colours can be ...

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  18. There are n seats round a table numbered 1,2, 3,..., n. The number of...

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  19. A shopkeeper sells three varieties of perfumes and he has a large numb...

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  20. If rgtpgtq, the number of different selections of p+q things taking r ...

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