how many ounces of 5% bismouth solution and 20% bismouth solution should be mixed together to get 10 ounces of a 15% bismouth solution?

When the solutions to each of the two equations below are graphed in the xy-coordinate plane, the graphs of the solutions intersect at two places. write the y-cordninates of the points of intersection in the boxes below in order from smallest to largest. y=2x y=x^2-3