Twenty marbles are used to spell a word—9 blue ones, 5 red ones, 3 yellow ones and 3 green ones. If two marbles are drawn from the set of twenty marbles at random in succession and without replacement, what is the probability (as a reduced fraction) of choosing a marble other than red each time?
there are 5 of 20 marbles that are red, so our chances of pulling two non-red ones are
15/20 * 14/19
just reduce that.