1. **State the problem:** We want to find the conditional probability that a card drawn from a standard 52-card deck is a heart, given that the card is red.
2. **Recall the formula for conditional probability:**
$$P(A|B) = \frac{P(A \cap B)}{P(B)}$$
where $A$ is the event "card is a heart" and $B$ is the event "card is red".
3. **Identify the events:**
- There are 52 cards total.
- Hearts are one of the four suits, with 13 cards.
- Red cards are hearts and diamonds, so there are $13 + 13 = 26$ red cards.
4. **Calculate $P(A \cap B)$:**
Since all hearts are red, $A \cap B$ is just the event "card is a heart," so
$$P(A \cap B) = \frac{13}{52} = \frac{1}{4}$$
5. **Calculate $P(B)$:**
$$P(B) = \frac{26}{52} = \frac{1}{2}$$
6. **Apply the conditional probability formula:**
$$P(A|B) = \frac{P(A \cap B)}{P(B)} = \frac{\frac{1}{4}}{\frac{1}{2}}$$
7. **Simplify the fraction:**
$$P(A|B) = \frac{1}{4} \times \frac{2}{1} = \frac{2}{4} = \frac{1}{2}$$
**Final answer:** The probability that the card is a heart given that it is red is $\boxed{\frac{1}{2}}$.
Conditional Probability 61A247
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.