Question 1190209
<pre>
PRICE     QUANTITY      COST
  4         x           4x
  6         y           6y
 10         x+y        10(x+y)
  7.6       100        14x+16y
</pre>
{{{system(2x+2y=100,14x+16y=760)}}}


{{{system(x+y=50,7x+8y=380)}}}

.

.

or if substituting, {{{7(50-y)+8y=380}}}

{{{350+y=380}}}

{{{highlight(y=30)}}}
{{{and}}}
{{{highlight(x=20)}}}.