3/12, or 1/4 is the probability that it is blue.
What is probability?
Probability = number of successes / total number of outcomes
Total marbels in bag = 4+ 3 + 5 = 12
A total of 12 marbles are in the bag.
3 blue marbles are in the bag.
Therefore, the probability of picking a blue is 3/12, or 1/4.
Learn more about probability
brainly.com/question/14740947
#SPJ4