Question 982962
{{{3x+2y=z}}}
{{{9x=z}}}
Substituting,
{{{3x+2y=9x}}}
{{{2y=6x}}}
So then multiplying both sides by {{{3/2}}},
{{{3x=9y=z}}}
So you can buy 3 ice cream cones for the same price of 9 chocolate bars. 
Well done.