<PRE><B>Question 1100820</B>
A family consist of a mother, a father, and some children.
 The average age of the family is 20, the father is 48 years old, and the average age of the mother and children is 16.
How many children are in the family? 
:
let c = no. of children


{{{(48 + 16(c+1))/(c+2) = 20}}} 
48 + 16c + 16 = 20(c+2)
64 + 16c = 20c + 40
64 - 40 = 20c - 16c
24 = 4c
c = 24/4
c = 6 children in the family
:
:
Check:
{{{(48 + 16(7))/8}}} = 20
{{{(48 + 112)/8}}} = 20</PRE>