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.
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
To find the probability that the marble is blue or red, we first need to determine the total number of marbles in the bag.
The bag contains 7 blue marbles, 5 red marbles, and 9 green marbles, which gives us a total of 7 + 5 + 9 = 21 marbles.
The probability of selecting a blue or red marble is the number of favorable outcomes (blue or red marbles) divided by the number of total outcomes (all marbles).
The number of favorable outcomes is 7 (number of blue marbles) + 5 (number of red marbles) = 12.
Therefore, the probability of selecting a blue or red marble is 12/21.
Simplifying this fraction, we get 4/7 as the final answer.