Question 738522
"For every 3 teenagers, 8 children went to the zoo."
That is simply a ratio between two variables.  It does not give you enough information for another equation.  Use the ratio to simplify your current system so it has TWO variables instead of THREE variables.  


You can use the ratio either as {{{(3_teenagers/ 8_children)}}} or {{{(8_children/3_teenagers)}}}.  Take your pick, but convert the t or the c in your current system of equations, not both.