In a college, the average weight of 40 boys in a section among 72 students is 33 kg and that of the remaining students is 15 kg. What is the average weight of all the students in the section?

The correct answer is 25 kg.

To find the overall average weight of all the students in the section, we can use the formula for weighted average:

$\text{Overall Average Weight}=\frac{\text{Total weight of all students}}{\text{Total number of students}}$

Step 1: Identify the given values.
Total number of students = 72
Number of boys = 40
Average weight of the 40 boys = 33 kg
Number of remaining students = 72 - 40 = 32
Average weight of the remaining 32 students = 15 kg

Step 2: Calculate the total weight of the 40 boys.
$\text{Total weight of 40 boys}=40\times 33=1320\text{kg}$

Step 3: Calculate the total weight of the remaining 32 students.
$\text{Total weight of remaining students}=32\times 15=480\text{kg}$

Step 4: Calculate the total weight of all 72 students.
$\text{Total weight}=1320+480=1800\text{kg}$

Step 5: Calculate the average weight of all 72 students.
$\text{Average weight}=\frac{1800}{72}=25\text{kg}$

Thus, the average weight of all the students in the section is 25 kg.