What is the probability of selecting a red marble from a bag containing 3 red, 2 blue, and 5 green marbles?

To determine the probability of selecting a red marble from the bag, it's essential to look at the total number of marbles and how many of those are red.

In the bag, there are:

• 3 red marbles

• 2 blue marbles

• 5 green marbles

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

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

Now, we need to find the probability of selecting a red marble. The probability is calculated using the formula:

Probability of an event = (Number of favorable outcomes) / (Total number of outcomes).

In this case, the "favorable outcomes" are the number of red marbles, which is 3, and the "total outcomes" is the total number of marbles, which is 10. Therefore, the probability of selecting a red marble is:

Probability of selecting a red marble = 3 (red marbles) / 10 (total marbles) = 3/10.

This calculation shows that the chance of picking a red marble is indeed 3 out of 10, making this choice the correct answer.