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Some couples participated in a mixed doubles badminton tournament. If the number of matches played, so
that no couple in a match, is 840, then the total numbers of persons, who participated in the tournament, is
____.

Option: 1

16


Option: 2

-


Option: 3

-


Option: 4

-


Answers (1)

best_answer

Let number of couples = n

\therefore \, \, ^{n}C_2\times ^{n-2}C_2\times 2=840

\Rightarrow n(n-1)(n-2)(n-3)=840\times 2

=21\times 40\times 2\\

=7\times 3\times 8\times 5\times 2

n(n-1)(n-2)(n-3)=8\times 7\times 6\times 5\\\therefore n=8

Hence, number of persons = 16.

 

Posted by

Gautam harsolia

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