Question

The mean age of a combined group of men and women is $25$ years. If the mean age of the group of men is $26$ and that of the group of women is $21$, then the percentage of men and women in the group is

• A. $60,40$
• B. $80,20$
• C. $20,80$
• D. $40,60$

Answer 1

Answer: (B)

$80,20$

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 = $\frac{sumofagesinthegroup}{noofpeople}$
Total sum = sum of ages of men + sum of ages of women
$\Rightarrow 100\times 25=x\times 26+(100-x)\times 21$
$\Rightarrow x=80$
Hence, the percentage of men and women in the group is $80,20$ respectively