In a class of 60 students, there are 35 boys. The average weight of boys is 42 kg and the average weight of the full class is 46.5 kg. Find the average weight of girls in the class.
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 52.8 kg.
Average = Sum of observations/Number of observations
We have,
Sum of the weight of 60 students = 60 × 46.5 = 2790
Sum of the weight of 35 boys = 35 × 42 = 1470
Total number of girls = 60 - 35 = 25
Hence, the average weight of 25 girls = (2790 - 1470)/(60 - 35)
⇒ 1320/25 = 52.8 kg