To find the probability of drawing 2 purple marbles from a bag of 25 marbles, we need to use the formula for probability without replacement.
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Determine the total number of marbles and the number of purple marbles:
- Total marbles = 25
- Purple marbles = 4
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Calculate the probability of drawing the first purple marble: \[ P(\text{1st purple}) = \frac{4}{25} \]
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Calculate the probability of drawing the second purple marble after the first one has been drawn (without replacement):
- Once the first purple marble is drawn, there are now 3 purple marbles left and a total of 24 marbles remaining. \[ P(\text{2nd purple | 1st purple}) = \frac{3}{24} = \frac{1}{8} \]
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Now, calculate the combined probability of both events happening (drawing 2 purple marbles): \[ P(\text{2 purple}) = P(\text{1st purple}) \times P(\text{2nd purple | 1st purple}) = \frac{4}{25} \times \frac{3}{24} \] \[ P(\text{2 purple}) = \frac{4 \times 3}{25 \times 24} = \frac{12}{600} = \frac{1}{50} \]
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Convert the fraction to a percentage: \[ P(\text{2 purple}) = \frac{1}{50} = 0.02 \text{ as a decimal} \] To convert to a percentage, multiply by 100: \[ 0.02 \times 100 = 2% \]
Thus, the probability of drawing 2 purple marbles is 2%.
The correct answer is D. 2%.