Probability Ques 31
Question-
A bag contains 4 white and 5 blue balls. Another bag contains 5 white and 7 blue balls. What is the probability of choosing two balls one from each bag such that one is white and the other is blue?
(1) $\frac{15}{78}$
(2) $\frac{25}{67}$
(3) $\frac{11}{45}$
(4) $\frac{53}{108}$
(5) $\frac{10}{37}$
(IBPS Bank PO/MT CWE (Main Exam) 18.11.2018)
Show Answer
Correct Answer: (4)
Solution: (4)
Case I: Ball from first bag is white, from another is blue So probability $=\left(\frac{4}{9}\right) \times\left(\frac{7}{12}\right)=\frac{28}{108}$
Case II: Ball from first bag is blue, from another is white So probability $=\left(\frac{5}{9}\right) \times\left(\frac{5}{12}\right)=\frac{25}{108}$
Add the cases So required probability $=\left(\frac{28}{108}\right)+\left(\frac{25}{108}\right)=\frac{53}{108}$
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