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  • Please,please help me In a family, there are 8 men, 7 women and 5 children whose mean ages separately are respectively 24, 20 and 6 years. The mean age of the family is

In a family, there are 8 men, 7 women and 5 children whose mean ages separately are respectively 24, 20 and 6 years. The mean age of the family is

  • Option 1)

    17.1 years

  • Option 2)

    18.1 years

  • Option 3)

    19.1 years 

  • Option 4)

    None of these 

 

Answers (1)

best_answer

As we have learned

Combined Mean -

If x1 and x2 be the means of two related groups having n1 and n2 items respectively then the combined mean \bar{x} of both the groups is given by 

\bar{x}= \frac{n_{1}\bar{x_{1}}+n_{2}\bar{x_{2}}}{n_{1}+n_{2}}

-

 

Here we have three collections for which A1 = 24, n1 = 8, A2 = 20, n2 = 7 and A3 = 6,
n3 = 5. Their combined mean is the required mean.

                By the formula A=\frac{n_1A_1+n_2A_2+n_3A_3}{n_1+n_2+n_3}

                  A=\frac{8\times 24+7\times 20+5\times 6}{8+7+3 }

                                = =\frac{192+140+30}{20 }=\frac{362}{20}=18.1 

 


Option 1)

17.1 years

Option 2)

18.1 years

Option 3)

19.1 years 

Option 4)

None of these 

Posted by

Himanshu

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