Question 1146152
Freddi, f
Grandson, g
{{{system(f+4=8g,f+g>67)}}}


{{{f=8g-4}}}
-
{{{(8g-4)+g>67}}}
{{{9g-4>67}}}
{{{9g>71}}}
{{{g>71/9}}}


In whole numbers, g should be at least 8 years.