AMC 10A 2007 Problem 10

The Dunbar family consists of a mother, a father, and some children. The average age of the members 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?

Answer Choices
A. 2
B. 3
C. 4
D. 5
E. 6