Answer :
Let the age of Justin be x years .
And Pyton is three years younger than Justin, therefore Peyton age is
[tex](x-3)years[/tex]
And Matt is four times as old as Peyton, therefore Matt age is
[tex]4(x-3) years[/tex]
And it is given that
[tex]x+x-3+4(x-3)=39[/tex]
[tex]x+x-3+4x-12=39 \\ 6x-15=39 \\ 6x=54 \\ x =9 years[/tex]
Therefore , Justin is 9 years old, Peyton is 6 years old and Matt is 24 years old .