Question 1145606
x, the son
y, the father
{{{system(x-3+y-3=48,y+3=3(x+3))}}}


{{{system(x+y=54,3x+9=y+3)}}}


{{{system(x+y=54,3x-y=-6)}}}


ADD:  {{{4x=48}}}


{{{x=12}}}------son
--
{{{y=42}}}------father