Question

the average age of 5 children is 8 years. if the age of the father is included , the average increased by 7 years. find the age of the father.

Answer 1

S = sum of the children's ages

Average of the 5 children's ages:

av = S / 5 = 8

S / 5 = 8

Multiply both sides by 5

S = 8 ∙ 5

S = 40

Sum of 5 children ages = 40


Let the father's age = f

The average, of 6 persons ( 5 children and the father):

( S + f ) / 6 = 8 + 7

( S + f ) / 6 = 15

( 40 + f ) / 6 = 15

Multiply both sides by 6

40 + f = 15 ∙ 6

40 + f = 90

Subtract 40 to both sides

40 + f - 40 = 90 - 40

f = 50

So the father is 50 years old

Answer 2

The average age of four childrens is 8 years which is incredible for year when the age of the father is included find the age of the father