The average weight of a class of 24 students is 35 kg. If the weight of the teacher be included, the average rises by 400 g. The weigliff the teacher is

Options

A. 45
B. 50
C. 55
D. 60

Answer

To find the weight of the teacher based on the given information, we can follow these steps:

### Step 1: Calculate the total weight of the students
The average weight of the 24 students is given as 35 kg. Therefore, we can calculate the total weight of the students using the formula:

\[ \text{Total weight of students} = \text{Number of students} \times \text{Average weight} \]

\[ \text{Total weight of students} = 24 \times 35 = 840 \text{ kg} \]

### Step 2: Determine the new average weight when the teacher is included
When the teacher's weight is included, the average weight increases by 400 grams. Since 400 grams is equal to 0.4 kg, the new average weight becomes:

\[ \text{New average weight} = \text{Old average weight} + \text{Increase} \]

\[ \text{New average weight} = 35 + 0.4 = 35.4 \text{ kg} \]

### Step 3: Calculate the total weight with the teacher included
Now that we have the new average weight with the teacher included, we can calculate the total weight of the class including the teacher:

\[ \text{Total weight with teacher} = \text{Number of students + teacher} \times \text{New average weight} \]

\[ \text{Total weight with teacher} = 25 \times 35.4 = 885 \text{ kg} \]

### Step 4: Find the weight of the teacher
To find the weight of the teacher, we subtract the total weight of the students from the total weight with the teacher included:

\[ \text{Weight of teacher} = \text{Total weight with teacher} - \text{Total weight of students} \]

\[ \text{Weight of teacher} = 885 - 840 = 45 \text{ kg} \]

### Conclusion
Thus, the weight of the teacher is **45 kg**.

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