There are two sections A and B of a class, consisting of 36 and 44 students respectively. If the average weight of sections A is 40 kg and that of section B is 35 kg. Find the average weight of the whole class (in kg).

Answer

To find the average weight of the whole class, we will follow these steps:

### Step 1: Calculate the total weight of Section A
The average weight of Section A is given as 40 kg, and there are 36 students in this section.

Total weight of Section A = Average weight × Number of students
\[ \text{Total weight of Section A} = 40 \, \text{kg} \times 36 = 1440 \, \text{kg} \]

### Step 2: Calculate the total weight of Section B
The average weight of Section B is given as 35 kg, and there are 44 students in this section.

Total weight of Section B = Average weight × Number of students
\[ \text{Total weight of Section B} = 35 \, \text{kg} \times 44 = 1540 \, \text{kg} \]

### Step 3: Calculate the total weight of the whole class
Now, we will add the total weights of both sections to find the total weight of the whole class.

Total weight of the whole class = Total weight of Section A + Total weight of Section B
\[ \text{Total weight of the whole class} = 1440 \, \text{kg} + 1540 \, \text{kg} = 2980 \, \text{kg} \]

### Step 4: Calculate the total number of students
Now, we will find the total number of students in both sections.

Total number of students = Number of students in Section A + Number of students in Section B
\[ \text{Total number of students} = 36 + 44 = 80 \]

### Step 5: Calculate the average weight of the whole class
Finally, we will find the average weight of the whole class by dividing the total weight by the total number of students.

Average weight of the whole class = Total weight of the whole class / Total number of students
\[ \text{Average weight of the whole class} = \frac{2980 \, \text{kg}}{80} = 37.25 \, \text{kg} \]

### Final Answer:
The average weight of the whole class is **37.25 kg**.

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