Question 1154614
The description would be best based on this:


Theater has 400 seats.
Orchestra Seats,  $70 each;
Main Seats, $60 each;
Balcony Seats, $35 each;
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Gross Revenue, $21300;

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If ALL the Main and Balcony seats sold and only HALF the Orchestra seats sold, Gross Revenue would be  $18500.


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r, Orchestra seats
m, Main seats
b, Balcony seats

{{{system(70r+60m+35b=21300,70(r/2)+60m+35b=18500,r+m+b=400)}}}



Look at the first two equations, and see that both of them contain the expression, {{{60m+35b}}}.  The value for r should be found very quickly because the description and resulting equations allows two variables to be easily eliminated.  Otherwise, solution methods may vary.