The average age of 7 members of a family is 40 years. In the family, there are three men, three women and one boy. If the average age of three men is 48 years and average age of three women is 44 years, then the age of the boy is:

Answer: Option C

According to the question,
Let the age of boy be x
7 × 40 = 3 × 48 + 3 × 44 + 1 × x
280 = 144 + 132 + x
x = 4
Therefore, age of the boy is = 4 years