Ecosystems form in response to the unique but predictable climate of each geographic area. And since elevation and topography affect climate, ecosystems are different at different elevations. The life in any given ecosystem is the direct result of elevation, topography, and temperature, and rainfall patterns.
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