If X and Y are jointly continuous with joint density function fx,y (x, y), show that X + Y is continuous with density function fx+Y (1) = [ fx,y(x,1 = x) dx 18 A box of chocolates contains 18 pieces, 9 of which have nuts while the remaining 9 do not. Four pieces are chosen at random. What is the probability that no more than one piece has nuts? 0.116 0.3125 0.289 0.444 0.517