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  • Tell me? Number of ways in which 3 boys and 3 girls (all of different height) can be arranged ina line so that boys as well as girls, among themselves, are in decreasing order of height (from left to right) is:

Number of ways in which 3 boys and 3 girls (all of different height) can be arranged in a line so that boys as well as girls, among themselves, are in decreasing order of height (from left to right) is:

  • Option 1)

    1

  • Option 2)

    6!

  • Option 3)

    20

  • Option 4)

    None of these

 

Answers (1)

best_answer

As we learnt in 

Number of arrangement of like and alike objects -

The number of arrangements that can be formed using n objects out of which r, q and p are identical objects then total number of arrangements=\frac{n!}{p!\ q!\ r!}

Ex. ALLAHABAD

A\rightarrow4

L\rightarrow2

\therefore\ \; \frac{9!}{4!\ 2!}

-

 

 3 Boys and 3 Girls

They can be arranged in \frac{6!}{3!3!}=\frac{720}{6\times 6}=20


Option 1)

1

Incorrect

Option 2)

6!

Incorrect

Option 3)

20

Correct

Option 4)

None of these

Incorrect

Posted by

prateek

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