Question 1147059
{{{ 8x + 12y = 120 }}}
There are many solutions for this, but most of
them involve decimals, for instance:
{{{ 8*6.5 + 12*5.667 = 120 }}}
{{{ 52 + 68 = 120 }}}
but, you can't have a fraction of a drink, so
only whole numbers work
{{{ x = 6 }}}
{{{ y = 6 }}}
are whole numbers that work.
There could be other solutions -I haven't checked.
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To solve the right way, you would need 
one more equation.