A bag contains 6 red marbles, 5 blue marbles, and 4 green marbles. If one marble is selected at random, what is the probability that it is green?

Step 1: Find the total number of marbles.

There are 6 red, 5 blue, and 4 green marbles.

Total = 6 + 5 + 4
Total = 15

Step 2: Identify the favorable outcomes.

We want to select a green marble.

There are 4 green marbles, so there are 4 favorable outcomes.

Step 3: Use the probability formula.

Probability = favorable outcomes / total outcomes

P(green) = 4 / 15

Step 4: Check whether the fraction can be simplified.

The numbers 4 and 15 have no common factor greater than 1, so 4/15 is already in simplest form.

As a decimal:
4/15 ≈ 0.2667

Therefore, the probability of selecting a green marble is 4/15, or approximately 0.2667.