Statistics And Probability Question 234

Question: A bag has 13 red, 14 green and 15 black balls. The probability of getting exactly 2 blacks on pulling out 4 balls is $ P_1. $ Now the number of each colour ball is doubled and 8 balls are pulled out. The probability of getting exactly 4 blacks is $ P_2. $ Then

Options:

A) $ P_1=P_2 $

B) $ P_1>P_2 $

C) $ P_1<P_2 $

D) None of these

Show Answer

Answer:

Correct Answer: B

Solution:

  •                  $ P_1=\frac{{}^{15}C_2\times {}^{27}C_2}{{}^{42}C_4}=\frac{27}{82} $                     and  $ P_2=\frac{{}^{30}C_4\times {}^{54}C_4}{{}^{84}C_8}=\frac{17\,.\,29\,.\,45\,.\,53}{11\,.\,79\,.\,82\,.\,83} $                                                                                (After simplification)                    Hence  $ P_1>P_2. $