set = 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15multiple of 3 = 6, 9, 12, 15multiple of 4 = 4, 8, 12Prob(multiple of 3 or 4) = Prob(multiple of 3) + pro(multiple of 4)= 412+312=712