Sales And Surveys
1. **QUESTION ONE: Organize sales data and calculate total sales for both groups**
- Kamukamu last month: 2520 litres milk, 35 bags maize, 10 bags beans
- Kamukamu this month: 3254 litres milk, 42 bags maize, 8 bags beans
- Tweziimbe last month: 2314 litres milk, 41 bags maize, 9 bags beans
- Tweziimbe this month: 2719 litres milk, 32 bags maize, 11 bags beans
- Price per litre milk = 700
- Price per kg maize = 1000
- Price per kg beans = 3500
- Each bag of maize or beans = 120 kg
Calculate total sales for each period:
1. Calculate total quantities sold (kg or litres) per group for each product:
Kamukamu last month maize = $35 \times 120 = 4200$ kg
Kamukamu last month beans = $10 \times 120 = 1200$ kg
Tweziimbe last month maize = $41 \times 120 = 4920$ kg
Tweziimbe last month beans = $9 \times 120 = 1080$ kg
Kamukamu this month maize = $42 \times 120 = 5040$ kg
Kamukamu this month beans = $8 \times 120 = 960$ kg
Tweziimbe this month maize = $32 \times 120 = 3840$ kg
Tweziimbe this month beans = $11 \times 120 = 1320$ kg
2. Calculate sales money for each group per period:
Last month Kamukamu sales:
Milk: $2520 \times 700 = 1,764,000$
Maize: $4200 \times 1000 = 4,200,000$
Beans: $1200 \times 3500 = 4,200,000$
Total Kamukamu last month = $1,764,000 + 4,200,000 + 4,200,000 = 10,164,000$
Last month Tweziimbe sales:
Milk: $2314 \times 700 = 1,619,800$
Maize: $4920 \times 1000 = 4,920,000$
Beans: $1080 \times 3500 = 3,780,000$
Total Tweziimbe last month = $1,619,800 + 4,920,000 + 3,780,000 = 10,319,800$
This month Kamukamu sales:
Milk: $3254 \times 700 = 2,277,800$
Maize: $5040 \times 1000 = 5,040,000$
Beans: $960 \times 3500 = 3,360,000$
Total Kamukamu this month = $2,277,800 + 5,040,000 + 3,360,000 = 10,677,800$
This month Tweziimbe sales:
Milk: $2719 \times 700 = 1,903,300$
Maize: $3840 \times 1000 = 3,840,000$
Beans: $1320 \times 3500 = 4,620,000$
Total Tweziimbe this month = $1,903,300 + 3,840,000 + 4,620,000 = 10,363,300$
3. Calculate total sales for both groups for each month:
Last month total sales = $10,164,000 + 10,319,800 = 20,483,800$
This month total sales = $10,677,800 + 10,363,300 = 21,041,100$
2. **QUESTION TWO: Evaluate whether at least 70% fit in two sizes**
Given:
- Students who fit medium = 100
- Students who fit large = 100
- Students who fit small = 76
- Students fit small & large = 50
- Students fit medium & large = 70
- Students fit small & medium = 60
- Students fit none = 4
- Class total = 140
- Some fit all three sizes
1. Find number fit in at least two sizes.
2. Use Inclusion-Exclusion for triple intersections:
Let $x$ = students who fit all three sizes.
Number fit in exactly two sizes = (sum of pairs) - 3x
Pairs sum = $50 + 70 + 60 = 180$
3. Total fit in none = 4, so total fit in at least one size = $140 - 4 = 136$
4. Total in exactly one size = (sum individuals) - (sum pairs) + x
Sum individuals = $76 + 100 + 100 = 276$
From inclusion-exclusion:
$$136 = 276 - 180 + x \Rightarrow x = 40$$
5. Calculate number fitting at least two sizes:
$$= \text{pairs sum} - 3x + x = 180 - 3\times40 + 40 = 180 - 120 + 40 = 100$$
6. Percentage with at least two sizes:
$$\frac{100}{140} \times 100 = 71.43\%$$
Since 71.43% > 70%, we will buy the suggestion. It satisfies the captain's condition.
3. **QUESTION THREE (a): Arrange foodstuffs bought and find which school spent most**
Prices:
Posho = 20,000
Rice = 30,000
Cassava = 10,000
Week 1 quantities (bags):
- Nalinya: Posho=2, Rice=1, Potatoes=3(not priced, ignore)
- Ndejje: Posho=2, Rice=2
- Sazza: Posho=1, Rice=1, Cassava=2
Week 2 quantities:
- Nalinya: Posho=3, Cassava=2
- Ndejje: Posho=1, Rice=2, Cassava=1
- Sazza: Posho=3, Cassava=1
Arrays (rows: schools, columns: foodstuffs posho, rice, cassava):
Week 1:
$$\begin{bmatrix}2 & 1 & 0 \\ 2 & 2 & 0 \\ 1 & 1 & 2\end{bmatrix}$$
Week 2:
$$\begin{bmatrix}3 & 0 & 2 \\ 1 & 2 & 1 \\ 3 & 0 & 1\end{bmatrix}$$
Price vector:
$$\begin{bmatrix}20000 \\ 30000 \\ 10000\end{bmatrix}$$
Calculate total spent per school:
Week 1 total per school:
- Nalinya: $2 \times 20000 + 1 \times 30000 + 0 = 70000$
- Ndejje: $2 \times 20000 + 2 \times 30000 + 0 = 100000$
- Sazza: $1 \times 20000 + 1 \times 30000 + 2 \times 10000 = 70000$
Week 2 total per school:
- Nalinya: $3 \times 20000 + 0 + 2 \times 10000 = 80000$
- Ndejje: $1 \times 20000 + 2 \times 30000 + 1 \times 10000 = 90000$
- Sazza: $3 \times 20000 + 0 + 1 \times 10000 = 70000$
Total for two weeks:
- Nalinya: $70000 + 80000 = 150000$
- Ndejje: $100000 + 90000 = 190000$
- Sazza: $70000 + 70000 = 140000$
Ndejje S.S spent the most.
3. **QUESTION THREE (b): Survey data analysis**
Given:
- Liked cassava (C) = 47
- Liked posho (P) = 53
- Liked rice (R) = 45
- Liked posho only = 23
- Liked cassava only = 10
- Liked rice only = 5
- Liked all three = 15
- All students liked at least one
(i) Arrange in Venn diagram categories:
Calculate exactly two sizes:
Posho and cassava only = $P \cap C - P \cap R \cap C - P \cap C \cap R??$
Total of sets:
$$|P \cup C \cup R| = ?$$
First find number liking exactly two foods:
Total in P = 53
Only P = 23
All three = 15
So:
Two food only involving P:
$$\text{two only} = |P| - |P \text{ only}| - |P \cap C \cap R| = 53 - 23 - 15 = 15$$
Similarly for C:
Two only for C:
$$47 - 10 - 15 = 22$$
Two only for R:
$$45 - 5 - 15 = 25$$
(ii) Number of students preferring at least two foods = sum exactly two + all three = $15 + 22 + 25 + 15 = 77$
(iii) Total students:
Sum all single only + exactly two + all three
Only P + only C + only R = 23 + 10 + 5 = 38
Exactly two = 15 + 22 + 25 = 62
All three = 15
Total = $38 + 62 + 15 = 115$
(iv) Probability student prefers rice:
$$\frac{45}{115} = 0.3913$$ (approx 39.13%)
Conclusion: Less than half prefer rice, so rice is less popular compared to other foodstuffs.