I don't understand how to do this and i have a test tomorrow over this

The graph represents the gallons of water in a water tank with respect to the number of hours since it was completely filled

To decrease an amount by 16% what single multiplier would you use

Find the volume of the solid whose base is the region bounded by f(x), g(x) and the x-axis on the interval [0, 1], and whose cross-sections perpendicular to the y-axis are squares. your work must show the integral, but you may use your calculator to evaluate it. give 3 decimal places for your answe