There are 5 blue marbles, 4 red marbles, and 3 yellow marbles in a box. If Jim randomly selects a marble from the box, what is the probability of selecting a red or yellow marble

The probabilty of selecting a red or yellow marble is 7/12

Step-by-step explanation:

To know the probability we have to divide the number of favorable events by the number of possible events

F = Favorable events: red or yellow marble

P = Possible events:  red, yellow or blue

F = 4 + 3

F = 7

P = 5 + 4 +3

P = 12

7/12

The probabilty of selecting a red or yellow marble is 7/12