Statistics And Probability Question 103

Question: In a knock out chess tournament, eight players $ P_1,P_2,…P_8 $ Participated. It is known that whenever the players $ P_{i} $ and $ P_{j} $ play, the player’s $ P_{i} $ will win j if $ i<j $ . Assuming that the players are parried at random in each round, what is the probability that the players $ P_4 $ reaches the final?

Options:

A) 31/35

B) 4/35

C) 8/35

D) None of these

Show Answer

Answer:

Correct Answer: B

Solution:

  • [b] Let us divide the players into two pools A and B each containing 4 players. Let $ P_4 $ be in pool A. now $ P_4 $ will reach the final if we fill the remaining three of pool A by any of $ P_5,P_6,P_7orP_{s} $ .
    $ \therefore $ Probability is $ \frac{^{4}C_3}{^{7}C_3}=\frac{4.3.2}{7.6.5}=\frac{4}{35}. $