In a locality 100 families were chosen at random and the following data was collected:
`|{:("Number of childeren"," 0 1 2 3 4 or more"),("is each family",),("Number of families"," 3 40 45 12 0"):}|`
If a family is chosen at random, find the probability that the chosen family has 3 or more children.

Answer

To solve the problem, we need to find the probability that a randomly chosen family has 3 or more children. Here's how we can do this step by step:

### Step 1: Understand the data
The data provided gives us the number of families based on the number of children they have:
- 0 children: 3 families
- 1 child: 40 families
- 2 children: 45 families
- 3 children: 12 families
- 4 or more children: 0 families

### Step 2: Determine the total number of families
From the data, we can see that the total number of families surveyed is:
\[ 3 + 40 + 45 + 12 + 0 = 100 \]
So, the total number of families is 100.

### Step 3: Identify families with 3 or more children
We need to find the number of families that have 3 or more children. According to the data:
- Families with 3 children: 12
- Families with 4 or more children: 0

Therefore, the total number of families with 3 or more children is:
\[ 12 + 0 = 12 \]

### Step 4: Calculate the probability
The probability \( P \) that a randomly chosen family has 3 or more children can be calculated using the formula:
\[ P(\text{3 or more children}) = \frac{\text{Number of families with 3 or more children}}{\text{Total number of families}} \]
Substituting the values we found:
\[ P(\text{3 or more children}) = \frac{12}{100} \]

### Step 5: Simplify the probability
To simplify \( \frac{12}{100} \):
\[ \frac{12}{100} = \frac{3}{25} \]

### Final Answer
The probability that a randomly chosen family has 3 or more children is:
\[ \frac{3}{25} \]

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