A theater has 500 seats, divided into orchestra, main, andbalcony seating. Orchestra seats sell for $50, main seats for $35,and balcony seats for $25. If all the seats are sold, the grossrevenue to the theater is $17,100. If all the main and balconyseats are sold, but only half the orchestra seats are sold, thegross revenue is $14,600. How many balcony seats are there?
