Fruit Survey 530709
1. **Problem Statement:** We have a survey about people liking apricots (A), bananas (B), and cantaloupes (C) with given counts and intersections. We want to find the number who liked all three fruits ($x$), total interviewed, and those who liked bananas and apricots but not cantaloupes.
2. **Given Data:**
- $|A|=39$
- $|B|=50$
- $|C|=39$
- $|A \cap B|=21$
- $|B \cap C|=18$
- $|A \cap C|=19$
- Number who liked exactly two fruits = 22
- Number who liked none = 8
3. **Key Formulas and Rules:**
- Number who liked exactly two fruits is sum of pairwise intersections minus thrice the triple intersection:
$$|A \cap B| + |B \cap C| + |A \cap C| - 3x = 22$$
- Total number interviewed is union plus those who liked none:
$$|A \cup B \cup C| + 8$$
- Inclusion-Exclusion Principle for union:
$$|A \cup B \cup C| = |A| + |B| + |C| - |A \cap B| - |B \cap C| - |A \cap C| + x$$
4. **Find $x$:**
From exactly two fruits:
$$21 + 18 + 19 - 3x = 22$$
$$58 - 3x = 22$$
$$3x = 58 - 22 = 36$$
$$x = \frac{36}{3} = 12$$
5. **Find total number interviewed:**
Calculate union:
$$|A \cup B \cup C| = 39 + 50 + 39 - 21 - 18 - 19 + 12 = 128 - 58 + 12 = 82$$
Add those who liked none:
$$82 + 8 = 90$$
6. **Find number who liked bananas and apricots but NOT cantaloupes:**
This is the part of $|A \cap B|$ excluding those who liked all three:
$$|A \cap B| - x = 21 - 12 = 9$$
**Final answers:**
- $x = 12$
- Total interviewed = 90
- Bananas and apricots but not cantaloupes = 9