Probability
Conditional Probability
MMTS_Full_Test_21
Grade 12
Question:
Three coins are tossed simultaneously. The probability that all coins have the same face up, given that at least one head shows, is
$\dfrac{1}{9}$
$\dfrac{1}{7}$
$\dfrac{1}{5}$
$\dfrac{1}{6}$
Step-by-Step Solution
Key Concept: $P(\text{all same}|\text{at least one H}) = P(\text{all H})/P(\text{at least one H})$
$P(\text{all H})=1/8$. $P(\text{at least one H})=7/8$. $P=\frac{1/8}{7/8}=1/7$.
Correct Answer: 3