Question 1154900
(1) {{{ 3x + 5y = 400 }}}
(2) {{{ x + y = 120 }}}
Here's the plot of the solution:
{{{ graph( 400, 400, -40, 200, -50, 200, 120 - x, (-3/5)*x + 80 ) }}}
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{{{ x = 40 }}}
{{{ y = 70 }}}
(1) {{{ 3*40 + 5*70 = 120 + 350 }}}
(1) {{{ 120 + 350 = 470 }}}
Yes, their goal would be met
There would be 10 empty seats, but they would 
make the goal.
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check:
Multiply both sides of (2) by {{{ 3 }}} and
subtract (1) from (2)
(1) {{{ 3x + 5y = 400 }}}
(2) {{{ -3x - 3y = -360 }}}
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{{{ 2y = 40 }}}
{{{ y = 20 }}}
and
(2) {{{ x + 20 = 120 }}}
(2) {{{ x = 100 }}}
Looks like a match to the plot
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