Step-by-step explanation:
In the bag, there are 12 marbles and 4 are yellow.
We need to find the probability that when choosing a marble at random the marble will be yellow.
The formula we use to calculate the probability is:
Here, the total number of events is 12 marbles, and the number of favorable events is the number of yellow marbles:
Since we need the answer as a fraction in the simplest form, we need to simplify our result.
4 and 12 can each be divided by 4, and the final probability is:
Answer: