I know in theory this is what everyone is saying but I just want to make sure I am doing it right algebraically. I haven't seen anyone create an equation linking x and y and substituting it. Does this take too much time? 1=X+Y --> Y=1-X (4/10)X+(1/4)Y = (3/10)(X+Y) (4/10)X+(1/4)(1-X) = (3/10)(x+(1-X...