Two cards are drawn successively with replacement from a well-shuffled deck of 52 cards. The probability distribution of number of aces is given by:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) →
|
X |
0 |
1 |
2 |
|
P(x) |
$\frac{144}{169}$ |
$\frac{24}{169}$ |
$\frac{1}{169}$ |
Let random variable $X$ = number of aces drawn in two draws (with replacement).
Probability of getting an ace in one draw: $p=\frac{4}{52}=\frac{1}{13}$
Probability of not getting an ace: $q=1-p=\frac{12}{13}$
Since draws are independent (with replacement), $X$ follows a Binomial distribution:
$n=2,\ p=\frac{1}{13}$
Hence,
$P(X=0)=\left(\frac{12}{13}\right)^{2}=\frac{144}{169}$
$P(X=1)=2\cdot\frac{1}{13}\cdot\frac{12}{13}=\frac{24}{169}$
$P(X=2)=\left(\frac{1}{13}\right)^{2}=\frac{1}{169}$
Probability distribution:
| $X$ | $P(X)$ |
|---|---|
| 0 | $\frac{144}{169}$ |
| 1 | $\frac{24}{169}$ |
| 2 | $\frac{1}{169}$ |