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If ""^(n)P(r) = 840 and ""^(n)C(r) = 35,...

If `""^(n)P_(r) = 840` and `""^(n)C_(r) = 35`, then r is equal to ………… .

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VMC MODULES ENGLISH-PERMUTATION & COMBINATION-JEE ARCHIVE
  1. If ""^(n)P(r) = 840 and ""^(n)C(r) = 35, then r is equal to ………… .

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  2. The number of integers greater than 6000 that can be formed using the ...

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  3. How many different nine-digit numbers can be formed from the digits of...

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  4. An n-digit number is a positive number with exactly n digits. Nine hun...

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  6. Eight chairs are numbered 1 to 8. Two women and three men wish to oc...

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  7. Ten different letters of an alphabet are given. Words with five letter...

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  9. Find the value of ""^(47)C4+ underset (r=1) overset( 5) sum ""^(52-r...

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  10. True or false 1. The product of any 2. r 3. 4. consecutive natural ...

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  11. The letters of the word COCHIN are permuted and all the permutation...

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  12. The number of arrangements of the letters of the word BANANA in whic...

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  18. Some identical balls are arranged in rows to form an equilateral trian...

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  19. There are m men and two women participating in a chess tournament. Eac...

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  20. A group of students comprises of 5 boys and n girls. If the number of ...

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  21. Let S be the set of all triangles in the xy-plane, each having one ver...

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