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Two different families A and B are blessed with equal number of children. There are
3 tickets to be distributed amongst the children of these families so that no child
gets more than one ticket. If the probability that all the tickets go to the children of the
family B is 1/12 , then the number of
children in each family is :

  • Option 1)

    3

  • Option 2)

    4

  • Option 3)

    5

  • Option 4)

    6

 

Answers (2)

best_answer

As we have learned 

Theorem of Combination -

Each of the different groups or selection which can be made by taking r things from n things is called a combination.

^{n}c_{r}=\frac{(n)!}{r!(n-r)!}

- wherein

Where 1\leq r\leq n

 

 _{3}^{x}\textrm{C}/_{3}^{2x}\textrm{C}=1/12=\frac{x(x-1)(x-2)}{2x(2x-1)(2x-2)}

\frac{x-2}{2x-1}=\frac{1}{3}\Rightarrow x=5

 

 

 

 


Option 1)

3

This is incorrect

Option 2)

4

This is incorrect

Option 3)

5

This is correct

Option 4)

6

This is incorrect

Posted by

Himanshu

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