If the goal is to sell at least $1500 worth of tickets then what you can do is add the 12.50+ 6.25 which well equal 18.75. Then you can divide 1500/18.75 which eqauls to 80 meaning at least 80 seats must be sold
The answer should be:
(x-4)^2 + (y+3)^2 = 6.25
hope this helped!