Julia and Kellen are participating in a read-a-thon to raise money for charity. The money each of them raises will be a mix of fixed and per-page donations. Function j models the total amount, in dollars, that Julia will raise if she reads x pages: j(x) = 1.65x + 17.31. Function k models the total amount, in dollars, that Kellen will raise if he reads x pages: k(x) = 0.90x + 9.28.