Probability Question 171
Question: Three coins are tossed. If one of them shows tail, then the probability that all three coins show tail, is
Options:
A) $ \frac{1}{7} $
B) $ \frac{1}{8} $
C) $ \frac{2}{7} $
D) $ \frac{1}{6} $
Show Answer
Answer:
Correct Answer: A
Solution:
Let $ E $ be the event in which all three coins shows tail and $ F $ be the event in which a coin shows tail.
$ F={HHT,HTH,THH,HTT,THT,TTH,TTT} $
and $ E={TTT} $ .
Required probability $ =P(E/F)=\frac{P(E\cap F)}{P(E)}=\frac{1}{7}. $
BETA
