Question 1117899
a, adults
c, children
{{{system(a+c=390,12a+5.5c=3991)}}}


Solve the system anyway you want.


--


{{{a=390-c}}}
-
{{{12(390-c)+5.5c=3991}}}
{{{4680-12c+5.5c=3991}}}
{{{-6.5c+4680=3991}}}
{{{-6.5c=3991-4680}}}
{{{6.5c=4680-3991}}}
{{{c=(4680-3991)/6.5}}}
-
{{{c=106}}}------children
{{{a=284}}}------adults