Final answer:
The probability of selecting a blue marble from the bag is 3 out of 12, which can be simplified to 1/4.
Step-by-step explanation:
The question asks us to find the probability of selecting a blue marble from a bag containing 2 red marbles, 3 blue marbles, and 7 green marbles. To find this probability, we divide the number of blue marbles by the total number of marbles in the bag. Since there are 3 blue marbles and a total of 12 marbles (2 + 3 + 7), the probability is 3/12. However, the fraction 3/12 can be reduced to its simplest form by dividing both the numerator and the denominator by their greatest common divisor, which is 3. Therefore, 3/12 simplifies to 1/4.
So, the simplest form of the probability of selecting a blue marble from the bag is 1/4.