A bag has 2 red marbles and 16 blue marbles. Half of the blue marbles are made of glass. A marble is selected at random from the bag. What is the probability that it is a blue, glass marble? Write your answer as a fraction in simplest form.
Add them up put 18 in denominator and desired amount in numerator which is 8, 8/ 18 then you get probability 4/9.