Three bad eggs are mixed with 7 good ones. If two eggs are drawn one by one without replacement, then the probability distribution of the number (X) of bad eggs drawn is: |
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The correct answer is Option (3) →
Total eggs = 3 bad + 7 good = 10 eggs Draw 2 eggs without replacement Random variable X = number of bad eggs drawn P(X=0): Both eggs are good $P(X=0) = \frac{7}{10} \cdot \frac{6}{9} = \frac{42}{90} = \frac{7}{15}$ P(X=1): One bad and one good (two orders) $P(X=1) = \frac{3}{10} \cdot \frac{7}{9} + \frac{7}{10} \cdot \frac{3}{9} = \frac{21}{90} + \frac{21}{90} = \frac{42}{90} = \frac{7}{15}$ P(X=2): Both eggs are bad $P(X=2) = \frac{3}{10} \cdot \frac{2}{9} = \frac{6}{90} = \frac{1}{15}$ Probability distribution: $X = 0 \; : \; \frac{7}{15}$ $X = 1 \; : \; \frac{7}{15}$ $X = 2 \; : \; \frac{1}{15}$ |