This yields a probability of (5/7) * (2/6) + (2/7) * (5/6) = 20/42. After replacing the blue marble, the probability of drawing two red marbles becomes (5/7) * (4/6) = 20/42. The final probability of drawing two red marbles in the second round is 20/42 * 20/42 = 400/1764. Simplified, this is 25/147, which is approximately 0.1701, or about 17.01%
