Question 1183458
x, the age for Sue
Age for Kim is x+12.


Combined Age:
{{{x+(x+12)=27}}}


{{{x+x+12=27}}}

{{{2x=27-12}}}

{{{2x=15}}}

{{{x=15/2}}}

{{{highlight(x=7&1/2)}}}
If you're looking for mixed units then  7 years 6 months.