AP EAMCET2010MathematicsProbability
An urn A contains 3 white and 5 black balls. Another urn B contains 6 white and 8 black balls. A ball is picked from A at random and then transferred to B . Then, a ball is picked at random from B . The probability that it is a white ball is
Options
- A14 40
- B15 40
- C16 40
- D17 40
Correct answer
D. 17 40
Step-by-step solution
Case Ist Let a white ball be transfered from the first bag to the second bag. The probability of selecting white ball from the first bag is P₁= 3 3+5 = 3 8 Now, the second bag has 7 white and 8 black balls. The probability of selecting a white ball from the second bag is P₂= 7 7+8 = 7 15 The probability that both these events take place simultaneously =P₁ P₂= 3 8 7 15 = 7 40 Case IInd Let a black ball be transfered from the first bag to the second bag. Its probability is P₃= 5 3+5 = 5 8 Now, the second bag contains