A bag contains 7 blue marbles, 5 red marbles, and 9 green marbles. A marble is taken at random from the bag. What is the probability that the marble is blue or red? Please type in your answer as a fraction.

4 answers

Either-or relationships require adding the probabilities of the individual events.

7/21 + 5/21 = ?
12/21
how many kinds of lunches are being served
7983