Answer: 1/3
Step-by-step explanation: In this problem, we're asked to find the probability of selecting a blue marble from a bag without looking.
Start with the ratio for the probability
of an event which is shown below.
P(event) = number of favorable outcomes/total number of outcomes
Since there are 3 blue marbles in a bag, the number of favorable outcomes is 3 and since there are 12 marbles in all and it's equally likely that we will choose any of the marbles, the total number of outcomes is 12 so we have 3/12.
Therefore, the probability of choosing a blue marble is 3/12.
However, notice that 3/12 can be reduced to 1/3.
So the final answer for the probability of choosing a blue marble is 1/3.
