Probability Question 53
Question: n cadets have to stand in a row. If all possible permutations are equally likely, then the probability that two particular cadets stand side by side, is
Options:
A) $ \frac{2}{n} $
B) $ \frac{1}{n} $
C) $ \frac{2}{(n-1)!} $
D) None of these
Show Answer
Answer:
Correct Answer: A
Solution:
Total number of ways $ =n! $ .
Favourable cases $ =2(n-1)! $
Hence required probability $ =\frac{2(n-1)!}{n!}=\frac{2}{n} $ .
BETA
