Paul works for a company that deals in paints and dyes. he is paid a fixed monthly salary plus 15 percent commission on monthly sales over $20,000. if paul manages to achieve total monthly sales of $x, which is over $20,000, the function f(x) representing paul's monthly sales over $20,000 is given by: a. x-20,000 b. x+20,000 c. 20,000-x d. 20,000/x if x is the sales amount over $20,000, the function g(x) giving paul's commission is: a. 0.15-x b. 0.15x c. 15-x/100 d. 0.15/x