A bag has 6 green marbles and 6 yellow marbles. Half of the yellow marbles are made of glass. A marble is selected at random from the bag. What is the probability that it is a yellow, glass marble?

Sample Space = {6 Green Marbles, 3 Yellow Glass, 3 Yellow Marbles} = 12

Favorable Event = { yellow AND Glass}

P (Yellow) = 6/12 = 1/2

P (Glass) = 3/12 = 1/4

P (Yellow ∩ Glass) = P (Yellow) x P (Glass) = (1/2). (1/4) = 1/8 = 0.125