Question

The mean age of a combined group of men and women is 25 years. If the mean age of the group of men 26 years and that of women is 21 years, find out percentage of men and women in the group.
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Answer 1

Explanation: Let total no. of people in the group be 100 and out of them x are men

i.e no of women = 100−x.

Mean age =  

no of people

sum of ages in the group

​Total sum = sum of ages of men + sum of ages of women

⇒100×25=x×26+(100−x)×21

⇒x=80

Hence, the percentage of men and women in the group is 80,20 respectively