Final answer:
The probability of drawing two red marbles from the bag can be found by calculating the ratio of the number of favorable outcomes to the total number of possible outcomes.
Step-by-step explanation:
To find the probability that both marbles drawn will be red, we need to calculate the ratio of the number of favorable outcomes to the total number of possible outcomes.
First, determine the number of ways to draw 2 red marbles from the bag. There are 8 red marbles in the bag, so the number of ways to choose 2 red marbles is given by the combination formula: C(8, 2) = 8! / (2! * (8 - 2)!) = 28.
Next, we need to determine the total number of possible outcomes. Since we are drawing 2 marbles without replacement, the total number of possible outcomes is given by the combination formula: C(21, 2) = 21! / (2! * (21 - 2)!) = 210.
Finally, calculate the probability by dividing the number of favorable outcomes by the total number of possible outcomes: P(2 red marbles) = 28 / 210 = 0.1333 (rounded to the nearest 1000th).