In a family, the average age of a father and a mother is 42 years. The average agge of the father, mother and their only son is 36 years. What is a the age of the son in years?

Correct option is B

Given:

1. The average age of the father and mother = 42 years.

2. The average age of the father, mother, and son = 36 years.

Formula Used:

Average Age = $$\frac{\text{Sum of ages}}{\text{Number of people}}$$​

Sum of ages = $$\text{Average Age} \times \text{Number of people}$$​

Solution:

1. Calculate the total age of the father and mother:

Sum of their ages = Average Age $$\times$$​ Number of people

Sum of their ages = 42 $$\times$$​2 = 84 years

2. Calculate the total age of the father, mother, and son:

Sum of their ages = 36 $$\times$$​ 3 = 108 years

3. Find the age of the son:

The total age of the father, mother, and son is 108 years. The total age of the father and mother is 84 years.

Age of the son = Total age of father, mother, and son - Total age of father and mother

Age of the son = 108 - 84 = 24 years

Final Answer:

The age of the son is 24 years.