iran-konkur 2019 Q138

iran-konkur · Other · konkur-riazi_1398_specialized_new-curriculum Conditional Probability Sequential/Multi-Stage Conditional Probability
138- In two boxes there are respectively 20 and 12 bulbs. In the first box 4 bulbs are defective and in the second box 3 bulbs are defective. From the first box 5 bulbs are randomly taken and placed in the second box. With what probability is a randomly selected bulb from the new second box defective?
(1) $\dfrac{5}{24}$ (2) $\dfrac{11}{48}$ (3) $\dfrac{13}{48}$ (4) $\dfrac{7}{24}$
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\textbf{138-} In two boxes there are respectively 20 and 12 bulbs. In the first box 4 bulbs are defective and in the second box 3 bulbs are defective. From the first box 5 bulbs are randomly taken and placed in the second box. With what probability is a randomly selected bulb from the new second box defective?

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(1) $\dfrac{5}{24}$ \hfill (2) $\dfrac{11}{48}$ \hfill (3) $\dfrac{13}{48}$ \hfill (4) $\dfrac{7}{24}$



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