Calculating Probability of Selecting a Blue Marble

In a bag, there are 3 red marbles, 5 blue marbles, and 2 green marbles. If a marble is selected at random from the bag, what is the probability that it will be a blue marble?

To find the probability of selecting a blue marble, use the formula:

$$ P( ext{Event}) = \f\frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} $$