The average weight of 16 boys in a class is 50.25 kg and that of the remaining 8 boys is 45.15 kg. Find the average weights of all the boys in the class.

Problem Restatement

Two groups of boys have different average weights. We need the overall (weighted) average for all 24 boys.

Given data

• Group 1: 16 boys, average = 50.25 kg
• Group 2: 8 boys, average = 45.15 kg
• Total boys = 16 + 8 = 24

Concept / Approach

The overall average is the weighted average: total weight of all students divided by total number of students. Do not average 50.25 and 45.15 directly because the group sizes are different.

Step-by-step calculation

Total weight (Group 1) = 16 × 50.25 = 804.00 kgTotal weight (Group 2) = 8 × 45.15 = 361.20 kgGrand total weight = 804.00 + 361.20 = 1165.20 kgOverall average = 1165.20 ÷ 24 = 48.55 kg

Common pitfalls

• Averaging 50.25 and 45.15 directly ignores different group sizes.
• Always convert each subgroup average into a sum first, then divide by the total headcount.

Final Answer

Average weight of all 24 boys = 48.55 kg.