If a bag contains 3 red, 2 blue, and 5 green marbles, what is the probability of randomly selecting a blue marble?

To determine the probability of randomly selecting a blue marble from the bag, you need to analyze the total number of marbles and how many of those are blue.

First, calculate the total number of marbles in the bag:

• Red marbles: 3
• Blue marbles: 2
• Green marbles: 5

Adding these together gives you:

3 (red) + 2 (blue) + 5 (green) = 10 total marbles.

Next, identify how many of these marbles are blue. There are 2 blue marbles.

The probability of selecting a blue marble is found by taking the number of blue marbles and dividing it by the total number of marbles:

Probability of blue marble = Number of blue marbles / Total number of marbles = 2 / 10.

This fraction simplifies to 1 / 5.

Understanding this process shows that the correct answer is based on the calculation of the proportion of blue marbles to the total marbles, leading to a probability of 1/5, confirming that the proper choice reflects this accurate assessment of odds in a simple random selection scenario.