Statistics And Probability Question 266
Question: Four boys and three girls stand in a queue for an interview, probability that they will in alternate position is
[UPSEAT 2001]
Options:
A) $ \frac{1}{34} $
B) $ \frac{1}{35} $
C) $ \frac{1}{17} $
D) $ \frac{1}{68} $
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Answer:
Correct Answer: B
Solution:
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Four boys can be arranged in $ 4\,! $ ways and three girls can be arranged in 3! ways.
$ \therefore $ The favourable cases $ =4,!,\times ,3,! $ Hence the required probability $ \frac{=4,!,\times 3,!}{7,!}=\frac{6}{7\times 6\times 5}=\frac{1}{35} $ .
BETA
