If there are 3 blue marbles, 2 red marbles, and 1 green marble in a bag, what is the probability of drawing 2 blue marbles if you replace the first one after you draw it?
The probability of drawing a blue marble on the first draw is 3/6, or 1/2. After replacing the first blue marble, there are still 3 blue marbles and 6 total marbles in the bag. Therefore, the probability of drawing a blue marble on the second draw is also 3/6, or 1/2. To find the probability of both events happening, we need to multiply the probabilities:
1/2 * 1/2 = 1/4
So the probability of drawing 2 blue marbles if you replace the first one after each draw is 1/4, or 0.25, or 25%.