Question 1160731
<pre>
Gabriela         x
Brother          x+8
Sister           x-12
TOTAL            50
</pre>
{{{x+(x+8)+(x-12)=50}}}


{{{3x+8-12=50}}}

{{{3x=54}}}

{{{highlight_green(x=18)}}}



<pre>
PERSON           AGE
Gabriela         18
Brother          x+8=26
Sister           x-12=6
TOTAL            50
</pre>