The average weight of 40 children of a class is 36.2 kg. When three more children with weight 42.3 kg, 39.7 kg and 39.5 kg join the class, the average weight of the 43 children In the class Is:

Options

A. 39.2 kg
B. 36.5 kg
C. 38.35 kg
D. 37.3 kg

Answer

To find the average weight of the 43 children after three more children join the class, we can follow these steps:

### Step 1: Calculate the total weight of the initial 40 children.
The average weight of the 40 children is given as 36.2 kg.

To find the total weight, we use the formula:
\[ \text{Total Weight} = \text{Average Weight} \times \text{Number of Children} \]
\[ \text{Total Weight of 40 children} = 36.2 \, \text{kg} \times 40 = 1448 \, \text{kg} \]

### Step 2: Calculate the total weight of the three new children.
The weights of the three new children are given as:
- Child 1: 42.3 kg
- Child 2: 39.7 kg
- Child 3: 39.5 kg

Now, we calculate their total weight:
\[ \text{Total Weight of 3 children} = 42.3 \, \text{kg} + 39.7 \, \text{kg} + 39.5 \, \text{kg} = 121.5 \, \text{kg} \]

### Step 3: Calculate the total weight of all 43 children.
Now, we add the total weight of the initial 40 children and the total weight of the 3 new children:
\[ \text{Total Weight of 43 children} = 1448 \, \text{kg} + 121.5 \, \text{kg} = 1569.5 \, \text{kg} \]

### Step 4: Calculate the average weight of the 43 children.
Finally, we find the average weight of the 43 children using the formula:
\[ \text{Average Weight} = \frac{\text{Total Weight}}{\text{Number of Children}} \]
\[ \text{Average Weight of 43 children} = \frac{1569.5 \, \text{kg}}{43} \approx 36.5 \, \text{kg} \]

### Conclusion:
The average weight of the 43 children in the class is approximately **36.5 kg**.

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