Question 1073339
{{{system(b/g=12/13,g-b=56)}}}



{{{b/(56+b)=12/13}}}


{{{13b=12(56+b)}}}


{{{13b=12*56+12b}}}


{{{b=12*56}}}


{{{highlight(b=672)}}}, the boys.


 and the number of girls, {{{g=728}}}.