Question 305589: The probability of randomly selecting a red marble from a bag, replacing it, and selecting a red marble again is 1/25. What is the probability of selecting a red marble on the first try? explain.
I know the 1/25 is a simplified result, so I am wondering if the first try is 1/5, then the 2nd try is 1/5, multiply across = 1x1 = 1, and 5x5 = 25, this is how I thing the answer is.
Answer by solver91311(24713)   (Show Source):
You can put this solution on YOUR website!
You are exactly right. Since you replaced the marble drawn on the first draw, the probabilities on each of the first and second draws are identical. Therefore, the probability of getting a red marble on the first draw is equal to the probability of getting a red one on the second draw, and the probability of both being red is the product of the two probabilities. That means the probability of the individual draws is the square root of the overall probability.
John
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