A city is planning to build a monument using Basalt, Granite, and Sandstone. The table below shows four rock types that will be considered for use in the project. Also shown for each rock type is its weight per volume, in pounds per cubic foot (lb/ft${}^3$), and the cost per pound, in dollars.

The rocks in the monument will have a total weight of 2,500 pounds. If 5 cubic feet of Basalt and 8 cubic feet of Granite are used, what is the volume, in cubic feet, of Sandstone used? Round your answer to the nearest hundredth.