A box contains colored marbles consisting of 5 red ones, 8 green ones, and 4 yellow ones. If a marble is drawn at random, what is the probability of drawing a red marble?
The probability of an event is the ratio between the number of
outcomes of the event and the number of all possible outcomes in
the sample space.
To find the probability that a randomly selected marble is red,
divide the number of red marbles in the box by the total number of
marbles in the box.