Venn Members
1. **State the problem:** We have a squash club with 27 members.
- 19 members have black hair.
- 14 members have brown eyes.
- 11 members have both black hair and brown eyes.
(i) We want to represent this on a Venn diagram.
(ii) Using this, we find:
I. The number of members with black hair or brown eyes.
II. The number of members with black hair but not brown eyes.
2. **Venn diagram construction:**
- Let set $B$ be members with black hair.
- Let set $E$ be members with brown eyes.
- We know the intersection $|B \cap E| = 11$.
3. **Calculate black hair only:**
$$|B \setminus E| = |B| - |B \cap E| = 19 - 11 = 8$$
4. **Calculate brown eyes only:**
$$|E \setminus B| = |E| - |B \cap E| = 14 - 11 = 3$$
5. **Calculate members with either black hair or brown eyes:**
Using the inclusion-exclusion principle:
$$|B \cup E| = |B| + |E| - |B \cap E| = 19 + 14 - 11 = 22$$
6. **Calculate members with black hair but not brown eyes:**
This is the black hair only group calculated in step 3:
$$8$$
**Final answers:**
I. Number of members with black hair or brown eyes = $22$
II. Number of members with black hair but not brown eyes = $8$