1. **Problem statement:** Re-examine the calculations for $n(J \cap V)$ and $n(R')$ given the sets defined over the months of the year.
2. **Step 1: Recall the sets:**
- $J = \{\text{January, June, July}\}$
- $V = \{\text{January, April, August, October}\}$
- $R = \{\text{October, December}\}$
- $U$ is all 12 months.
3. **Step 2: Find $n(J \cap V)$ correctly.**
- Intersection means elements in both $J$ and $V$.
- $J \cap V = \{\text{January}\}$ since January is the only month starting with J and a vowel.
- So, $n(J \cap V) = 1$ (this was correct initially).
4. **Step 3: Find $n(R')$ correctly.**
- $R' = U \setminus R$ means all months not ending with R.
- $R = \{\text{October, December}\}$
- Months ending with R are October and December only.
- So, $R' = \{\text{January, February, March, April, May, June, July, August, September, November}\}$
- Count elements: $n(R') = 10$ (this was also correct initially).
**Final answers confirmed:**
- $n(J \cap V) = 1$
- $n(R') = 10$
Set Operations 03564F
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