155. In two containers there are respectively 24 and 18 identical balls. In the first container there are 6 white balls and in the second container there are 3 white balls. From the first container 7 balls and from the second container 5 balls are randomly drawn and placed in another container. Then from the last container one ball is drawn. What is the probability that this ball is white? (1) $\dfrac{13}{72}$ (2) $\dfrac{7}{36}$ (3) $\dfrac{15}{72}$ (4) $\dfrac{31}{144}$ %% Page 28 Physics 120-C Page 10
\textbf{155.} In two containers there are respectively 24 and 18 identical balls. In the first container there are 6 white balls and in the second container there are 3 white balls. From the first container 7 balls and from the second container 5 balls are randomly drawn and placed in another container. Then from the last container one ball is drawn. What is the probability that this ball is white?
(1) $\dfrac{13}{72}$ \hfill (2) $\dfrac{7}{36}$
(3) $\dfrac{15}{72}$ \hfill (4) $\dfrac{31}{144}$
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\textbf{Physics \hfill 120-C \hfill Page 10}
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