Population Distribution by Continent:

- 2 billion in the Americas
- 1 billion in Europe
- 1 billion in Africa
- 3 billion in Australia and Asia

Question 9: How many of the world's 1-year-old children today have been vaccinated against some disease?

A. 20%
B. 50%
C. 80%



Answer :

Sure, let's break this down step by step to determine how many 1-year-old children have been vaccinated against some disease based on the given data.

### Step 1: Determine the total population

We need to add the populations of the different regions to find the total population of 1-year-old children:
- Population of the Americas: 2 billion
- Population of Europe: 1 billion
- Population of Africa: 1 billion
- Population of Australia and Asia: 3 billion

Adding these together:

[tex]\[ \text{Total population} = 2 + 1 + 1 + 3 = 7 \text{ billion} \][/tex]

### Step 2: Determine the vaccination rate

The problem states that the vaccination rate is 20%. This means that out of the total population of 1-year-old children, 20% have been vaccinated.

### Step 3: Calculate the number of vaccinated children

We need to find 20% of the total population. To do this, we multiply the total population by the vaccination rate:

[tex]\[ \text{Number of vaccinated children} = \text{Total population} \times \text{Vaccination rate} \][/tex]

Using the numbers we have:

[tex]\[ \text{Number of vaccinated children} = 7 \text{ billion} \times 0.20 = 1.4 \text{ billion} \][/tex]

### Conclusion

Based on the provided data, 1.4 billion of the world's 1-year-old children have been vaccinated against some disease.