A bag has 8 red marbles and 6yellow 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?

Well, there are 14 marbles total, and 3 of them are yellow glass ones, which means that 11 of the other marbles are not glass. If 14 marbles = 100% of the bag, then 3 marbles = x%

(If there were 15 marbles in the bag, then this question would be a bit easier to answer, but it's not)

100% - y% = x%

or...

100% - x% = y%

To answer this question, you need to figure out what either x or y is. y is the percentage of the 11 marbles which are not glass yellow ones, and x being the percentage of the 3 yellow glass marbles.

About 40%. It's not exact, but it's as close as I could get. I hope that this helps.