A group of people consists of men, women and children. Among them, 20% are men, 50% are women and the rest are children, and their average weights are 45 kg, 60 kg and 20 kg, respectively. The average weight (in kg) of the group is:​

Correct option is B

Given:

Composition: Men = 20%, Women = 50%, Children = 30% (rest).

Average weights: Men = 45 kg, Women = 60 kg, Children = 20 kg.

Formula Used:

Weighted mean =$$\sum (\text{proportion}) \times (\text{group mean})$$​​

Solution:
​$$\bar{W}=0.20\times45 + 0.50\times60 + 0.30\times20$$​​
= 9 + 30 + 6 = 45 kg