Question 965112
<pre>
James              2x
Dad                2x+5*2x=12x
Sara, sister        x
SUM, in two years   58
</pre>
{{{2x+12x+x+2+2+2=58}}}

.

.

{{{x=52/15=highlight_green(3&7/15)}}}, just for Sara's age.
Fifteenths is not the best denomination for time based on some years.  Wanted are denominations of months, or weeks, or days, or whole years.


Recheck the problem description.