Probability of Selecting Red or Blue Marble

A jar contains a mix of red, blue, and green marbles. Specifically, there are 5 red marbles, 7 blue marbles, and 8 green marbles. If you randomly select one marble from the jar, what is the probability that the marble selected is either red or blue?

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

$$ P(A) = \f\frac{n(A)}{n(S)} $$

where n(A) is the number of favorable outcomes (red or blue) and n(S) is the total number of outcomes (total marbles).