1. **State the problem:**
We have the universal set $U$ as the months of the year: \{January, February, March, April, May, June, July, August, September, October, November, December\}.
Sets are defined as:
- $J = \{x \in U \mid x \text{ begins with } J\}$
- $Y = \{x \in U \mid x \text{ ends with } Y\}$
- $V = \{x \in U \mid x \text{ begins with a vowel}\}$
- $R = \{x \in U \mid x \text{ ends with } R\}$
We need to find:
1. $n(V \cap R)$
2. $n(R')$
3. $n(J \cup Y)$
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2. **Identify the elements of each set:**
- $U = \{$January, February, March, April, May, June, July, August, September, October, November, December$\}$
- $J = \{$January, June, July$\}$ (months starting with J)
- $Y = \{$January, May, July$\}$ (months ending with Y)
- $V = \{$January, April, August, October$\}$ (months starting with vowels A, E, I, O, U)
- $R = \{$September, October, November, December$\}$ (months ending with R)
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3. **Calculate $n(V \cap R)$:**
Find months that start with a vowel and end with R.
- $V = \{$January, April, August, October$\}$
- $R = \{$September, October, November, December$\}$
Intersection $V \cap R = \{$October$\}$
So, $n(V \cap R) = 1$
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4. **Calculate $n(R')$:**
$R'$ is the complement of $R$ in $U$, i.e., months not ending with R.
Since $n(U) = 12$ and $n(R) = 4$,
$$n(R') = n(U) - n(R) = 12 - 4 = 8$$
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5. **Calculate $n(J \cup Y)$:**
Union of $J$ and $Y$ includes all months that start with J or end with Y.
- $J = \{$January, June, July$\}$
- $Y = \{$January, May, July$\}$
Union $J \cup Y = \{$January, June, July, May$\}$
So, $n(J \cup Y) = 4$
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**Final answers:**
$$n(V \cap R) = 1$$
$$n(R') = 8$$
$$n(J \cup Y) = 4$$
Set Cardinality F58D8B
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