The correct option is option (d).
Using Average formula,
the number of children in Dunbar family are 6 .
We have given that,
A Dunbar family consists a number of members including childrens, mother , father.
the average age of family members = 20 years
Age of father = 48 years
Average age of mother and children= 16
we have to calculate that how many children are in family .
Average age of members = sum of all members age divided by total numbers of members
Let x be the number of the children and the mom.
total number of member in family = x+ 1
sum of ages of children and mother = 16 ( number of children and mother)
i.e sum of ages of children and mother = 16x
sum of all family members age = 48 + 16x
putting all known data in above formula we get,
( 48 + 16x )/ (x+1) = 20 --(2)
now, we solve the equation
cross multiplication in equation (2) we get,
48 + 16x = 20 ( x+1) = 20x + 20
=> 48-20 = 20x- 16x = 4x
=> x = 28/4 = 7
so, number of children and mother in Dunbar family is 7
number of children in family= 7 - 1(mother) = 6
Hence, number of childrens in family is 6 .
To learn more about Average, refer:
https://brainly.com/question/24233224
#SPJ4
Complete Question:
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 48years old, and the average age of the mother and children is 16. How many children are in the family?
a) 2
b) 3
c) 4
d) 6