6 sons + 1 sister + 2 parents = Total 9 people in the family.
6 sons+1 sister+2 parents=9 person
Total 9........(Dad + Mom=6Sons+1Sis = 9)
9( children) +2( father and mother=11 members in family.
A family, made up of 2 parents with children, has an average age of 20.
If you exclude one parent, who is 40, the average age drops to 15.
How many kids are in the family?