Probability Question 379
Question: A die is thrown three times. Getting a 3 or a 6 is considered success. Then the probability of at least two successes is
[DSSE 1981]
Options:
A) $ \frac{2}{9} $
B) $ \frac{7}{27} $
C) $ \frac{1}{27} $
D) None of these
Show Answer
Answer:
Correct Answer: B
Solution:
Required probability $ =P $ (exactly two) $ +P $ (exactly three) $ ={}^{3}C_2.{{( \frac{2}{6} )}^{2}}( \frac{4}{6} )+{}^{3}C_3{{( \frac{2}{6} )}^{3}}=\frac{2}{9}+\frac{1}{27}=\frac{7}{27} $ .
BETA
