Question

The oldest child in a family of four children is three times as old as the youngest. The two middle children are 19 and 23 years old. If the average age of the children is 28.5, how old is the youngest child?

Answer 1

18 years old

Solution:

Let x represent the age of the youngest child.

So the age of the oldest = 3x

If the ages of the two middle children are 19 and 23, and the average age of the four children is 28.5, let's go ahead and find x;

`\begin{gathered} ((x+19+23+3x))/(4)=28.5 \\ 4x+42=114 \end{gathered}`

Let's go ahead and subtract 42 from both sides;

`4x=72`

Dividing both sides by 4, we'll have;

`x=(72)/(4)=18`

Therefore, the youngest is 18 years old.