What is the probability of choosing a blue marble out of a bag containing 3 red, 1 green, 4 blue, and 2 yellow marbles.

2/5 because you add up all the number the total is your bottom part of the fraction, and the number of blue is the stop you should get 4/10 then simplify to 2/5

the probability of choosing a blue marble is 4/10 or 0.4 or 40%.

Step-by-step explanation:

the first thing you do is count all the marbles together which in this problem its 10. then you read what the question is asking you in this case 4 blue, so you make it a fraction 4/10. to make it a decimal, you divide 4 : 10 it will give you 0.4, and to make it a percent you you multiply 4*10, it will give you 40%.