The average weight of 16 students in a class is 50.25 kg, and that of the remaining 8 students is 45.15 kg. Find the average weight of all the students in the class.
Answer & explanation
Correct answer: option 3
Use the weighted average formula.
- 16 students have an average weight of 50.25 kg
- 8 students have an average weight of 45.15 kg
Total weight:
- First group: $16 \times 50.25 = 804\text{ kg}$
- Second group: $8 \times 45.15 = 361.2\text{ kg}$
Total weight of all students:
$804 + 361.2 = 1165.2\text{ kg}$
Total number of students:
$16 + 8 = 24$
Average weight:
$\frac{1165.2}{24} = 48.55\text{ kg}$