Correct Answer - Option 4 : 47.39 kg

**Given **

Average weight of 12 students = 46.25 kg

Average weight of 18 students = 48.15 kg

**Formula Used **

Average = Sum of Data/Number of Data

**Calculation **

Average of 30 students = [(12 × 46.25) + (18 × 48.15)]/30

⇒ (555 + 866.7)/30 = 47.39 kg

**∴ The average weight of all students in the class is 47.39 kg**