1. **Problem statement:**
We have a pack of 10 cards: 6 red cards numbered 1, 2, 3, 4, 5, 6 and 4 black cards numbered 1, 2, 3, 4.
We analyze two events for part (a):
- $R$: the card drawn is red
- $E$: the card drawn has an even number
We want to check if $R$ and $E$ are independent.
2. **Recall the independence rule:**
Two events $A$ and $B$ are independent if and only if
$$P(A \cap B) = P(A) \times P(B)$$
3. **Calculate probabilities:**
- Total cards: 10
- $P(R) = \frac{6}{10} = 0.6$
- Even numbers are 2, 4, 6. Cards with even numbers:
- Red even numbers: 2, 4, 6 (3 cards)
- Black even numbers: 2, 4 (2 cards)
- Total even cards: 5
- $P(E) = \frac{5}{10} = 0.5$
4. **Calculate $P(R \cap E)$:**
Cards that are both red and even are 2, 4, 6 in red, so 3 cards.
$$P(R \cap E) = \frac{3}{10} = 0.3$$
5. **Check independence:**
Calculate $P(R) \times P(E) = 0.6 \times 0.5 = 0.3$
Since
$$P(R \cap E) = P(R) \times P(E) = 0.3,$$
$R$ and $E$ are independent.
6. **Part (b) problem statement:**
Events:
- $B$: the card is black
- $T$: the card number is 2
7. **Calculate probabilities:**
- $P(B) = \frac{4}{10} = 0.4$
- Cards with number 2: red 2 and black 2, total 2 cards
- $P(T) = \frac{2}{10} = 0.2$
8. **Calculate $P(B \cap T)$:**
Cards that are black and number 2: only black 2 card, so 1 card.
$$P(B \cap T) = \frac{1}{10} = 0.1$$
9. **Check independence:**
Calculate $P(B) \times P(T) = 0.4 \times 0.2 = 0.08$
Since
$$P(B \cap T) = 0.1 \neq 0.08 = P(B) \times P(T),$$
$B$ and $T$ are not independent.
**Final answers:**
- (a) $R$ and $E$ are independent because $P(R \cap E) = P(R)P(E)$.
- (b) $B$ and $T$ are not independent because $P(B \cap T) \neq P(B)P(T)$.
Card Independence 8A37C9
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.