Answer :

To calculate the probability that a five-card poker hand dealt to you contains exactly 4 Aces, we need to follow these steps:

1. Understand the Total Setup:

- Total number of cards: [tex]\(52\)[/tex]
- Total number of aces: [tex]\(4\)[/tex]
- Hand size: [tex]\(5\)[/tex]

2. Calculate the Number of Favorable Outcomes:
- We need exactly 4 aces and 1 other card.

- Number of ways to choose 4 aces from the 4 aces available:
[tex]\[ \binom{4}{4} = 1 \][/tex]

- Number of ways to choose 1 other card from the remaining 48 cards (since we already used the 4 aces):
[tex]\[ \binom{48}{1} = 48 \][/tex]

- Therefore, the number of favorable outcomes (ways to get 4 aces and 1 other card) is:
[tex]\[ 1 \times 48 = 48 \][/tex]

3. Calculate the Total Number of Possible Outcomes:
- We need the number of ways to choose any 5 cards out of the total 52 cards:
[tex]\[ \binom{52}{5} \][/tex]

4. Calculate the Actual Numbers:
- The total number of ways to choose 5 cards from 52 is:
[tex]\[ \binom{52}{5} = 2598960 \][/tex]

5. Determine the Probability:
- The probability is the ratio of the number of favorable outcomes to the total number of possible outcomes:
[tex]\[ \text{Probability} = \frac{48}{2598960} \][/tex]

6. Simplify the Probability:
- Performing this division gives us:
[tex]\[ \frac{48}{2598960} \approx 1.846892603195124 \times 10^{-5} \][/tex]

Thus, the probability that a five-card poker hand dealt to you contains exactly 4 Aces is approximately [tex]\(1.8469 \times 10^{-5}\)[/tex] or in decimal form, approximately [tex]\(0.0000184689\)[/tex].