Both questions refer to this joint density function.

3.41 A candy company distributes boxes of choco- lates with a mixture of creams, toffees, and cordials. Suppose that the weight of each box is 1 kilogram, but the individual weights of the creams, toffees, and cor- dials vary from box to box. For a randomly selected box. let .X and Y represent the weights of the creams and the toffees, respectively, and suppose that the joint density function of these variables is elsewhere