Venn Diagram Counts D0Cacf
1. **State the problem:** We are given a Venn diagram with sets A and B inside a universal set E, and we need to find the number of elements in various sets.
2. **Recall definitions:**
- $n(A)$ is the number of elements in set A.
- $n(B)$ is the number of elements in set B.
- $n(A \cap B)$ is the number of elements common to both A and B.
- $n(E)$ is the total number of elements in the universal set E.
- $n(A \cup B)$ is the number of elements in either A or B or both.
- $n(B' \cap A)$ is the number of elements in A but not in B.
3. **Identify elements from the diagram:**
- Elements in A only: b, s, o
- Elements in A \cap B: a, n, r
- Elements in B only: f, h
- Elements outside A and B but inside E: d, w
4. **Calculate each requested value:**
- $n(A) = $ elements in A only + elements in A \cap B = 3 + 3 = 6$
- $n(B) = $ elements in B only + elements in A \cap B = 2 + 3 = 5$
- $n(A \cap B) = $ elements in overlap = 3$
- $n(E) = $ all elements inside rectangle = b, s, o, a, n, r, f, h, d, w = 10$
- $n(A \cup B) = n(A) + n(B) - n(A \cap B) = 6 + 5 - 3 = 8$
- $n(B' \cap A) = $ elements in A but not in B = b, s, o = 3$
5. **Final answers:**
- a. $n(A) = 6$
- b. $n(B) = 5$
- c. $n(A \cap B) = 3$
- d. $n(E) = 10$
- e. $n(A \cup B) = 8$
- f. $n(B' \cap A) = 3$