The Venn diagram shows some information about
all the 52 families in a village. C is a set of 37
families that have cattle, G is a set of 24 families
that have goats and S is the set of 20 families that
have sheep.
14-x
X
12-x
11-x
S
G
It is also given that 14 families have cattle and goats,
11 families have cattle and sheep, x families have all
three types of animals and another x families have
no animals.
(a) Find, in terms of x, the number of families
with
(i) cattle only,
(ii)
goats only,
(iii)
sheep only.
(b)
Find
(i)
the value of x,
[6]
(ii) the number of families with goats but
have no cattle.
[4]
4028/2 12012222



Answer :

Answer:

Step-by-step explanation:

To solve the problem involving the Venn diagram with the sets \( C \) (families with cattle), \( G \) (families with goats), and \( S \) (families with sheep), follow these steps:

### Given:

- Total families: 52

- Families with cattle (\( |C| \)): 37

- Families with goats (\( |G| \)): 24

- Families with sheep (\( |S| \)): 20

- Families with cattle and goats: 14

- Families with cattle and sheep: 11

- Families with all three animals: \( x \)

- Families with no animals: \( x \)

### (a) Find the number of families with:

#### (i) Cattle only

Using the principle of inclusion and exclusion for the set of families with cattle:

\[ |C| = |C \cap G| + |C \cap S| - |C \cap G \cap S| + \text{(cattle only)} \]

So:

\[ 37 = 14 + 11 - x + \text{(cattle only)} \]

Rearranging to solve for cattle only:

\[ \text{Cattle only} = 37 - 14 - 11 + x \]

\[ \text{Cattle only} = 12 + x \]

#### (ii) Goats only

Using the principle of inclusion and exclusion for the set of families with goats:

\[ |G| = |G \cap C| + |G \cap S| - |C \cap G \cap S| + \text{(goats only)} \]

Given \( |G \cap C| = 14 \) and we need \( |G \cap S| \). We can write:

\[ |G \cap C| = 14 \]

\[ |G \cap S| = 12 - x \]

Then:

\[ 24 = 14 + (12 - x) - x + \text{(goats only)} \]

\[ \text{Goats only} = 24 - 14 - (12 - x) + x \]

\[ \text{Goats only} = 24 - 14 - 12 + x + x \]

\[ \text{Goats only} = -2 + 2x \]

#### (iii) Sheep only

Using the principle of inclusion and exclusion for the set of families with sheep:

\[ |S| = |S \cap C| + |S \cap G| - |C \cap G \cap S| + \text{(sheep only)} \]

Given \( |S \cap C| = 11 \) and \( |S \cap G| = 12 - x \):

\[ 20 = 11 + (12 - x) - x + \text{(sheep only)} \]

\[ \text{Sheep only} = 20 - 11 - (12 - x) + x \]

\[ \text{Sheep only} = 20 - 11 - 12 + x + x \]

\[ \text{Sheep only} = -3 + 2x \]

### (b) Find:

#### (i) The value of \( x \)

Since the total number of families is 52, and \( x \) families have no animals:

\[ \text{Total families} = \text{Families with only cattle} + \text{Families with only goats} + \text{Families with only sheep} + \text{Families with cattle and goats only} + \text{Families with cattle and sheep only} + \text{Families with goats and sheep only} + \text{Families with all three} + \text{Families with no animals} \]

\[ 52 = (12 + x) + (-2 + 2x) + (-3 + 2x) + (14 - x) + (11 - x) + (12 - x) + x + x \]

\[ 52 = 12 + x - 2 + 2x - 3 + 2x + 14 - x + 11 - x + 12 - x + x + x \]

Combine and simplify:

\[ 52 = 12 - 2 + 11 - 3 + 14 + 12 + x \]

\[ 52 = 52 + 2x \]

To balance the equation:

\[ 0 = 2x \]

Thus:

\[ x = 0 \]

#### (ii) Number of families with goats but have no cattle

Substitute \( x = 0 \) in the formula for goats only:

\[ \text{Goats only} = -2 + 2 \times 0 = -2 \]

Recheck calculations:

\[ \text{Families with goats but no cattle} = \text{Total goats} - \text{Families with goats and cattle} \]

\[ \text{Goats but no cattle} = 24 - 14 = 10 \]

### Summary:

- **(a)**

 - (i) Cattle only: \( 12 + x = 12 \)

 - (ii) Goats only: \( -2 + 2x = 10 \)

 - (iii) Sheep only: \( -3 + 2x = 7 \)

- **(b)**

 - (i) \( x = 0 \)

 - (ii) Families with goats but no cattle: 10