Probability Question 341
Question: Four persons are selected at random out of 3 men, 2 women and 4 children. Find the probability that there exactly 2 children in the selection.
Options:
A) $ \frac{11}{21} $
B) $ \frac{8}{21} $
C) $ \frac{10}{21} $
D) $ \frac{7}{21} $
Show Answer
Answer:
Correct Answer: C
Solution:
Total number of ways in which 4 persons can be selected out of $ 3+2+4=9 $ persons $ ={{}^{9}}C_4 $
$ =126. $ Number of ways in which a selection of 4 contains exactly 2 children $ {{=}^{4}}C_2{{\times }^{5}}C_2=60. $
$ \therefore $ Require probability $ =\frac{60}{126}=\frac{10}{21} $
BETA
