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The number of ways in which 20 different...

The number of ways in which 20 different pearls of two colours can be set alternately on a necklace, there being 10 pearls of each colour, is:

A

`9!xx10!`

B

`5xx(9!)^(2)`

C

`(9!)^(2)`

D

none of these

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

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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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