A bag contains 7 red marbles, 12 orange marbles, 18 yellow marbles, and 5 purple marbles. A marble is drawn at random from the bag. What is the probability that the marble drawn will not be orange?
There are 42 marbles in the bag.
When one marble is taken out at random, in terms of orange, there are only two possible outcomes:
either the marble IS orange, or it ISN'T.
There are 12 marbles which ARE orange, which means that the rest are NOT orange.
This can also be shown as;