What is the percentage of 199.50 out of 286?

I'm confused on this could anyone me and show me what i need to do to solve it.

Solve the following pair of equations for x and y: ax/b_ by /a= a +b; ax - by = 2ab

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