Question

The average weight of 20 students of class XII is 45 kg. If the one student whose weight is 40 kg left the class and 2 new students are added due to this the average weight of class increased by 1 kg, then find the average weight of 2 new students.

 

1. 40 kg
2. 50 kg
3. 53 kg
4. 48 kg 

Answer 1

Correct Answer - Option 3 : 53 kg

Given 

The average weight of 20 students = 45 kg 

The weight of student who left the class = 40 kg

Formula Used 

Average = Sum of observation/Number of observation

Calculation

⇒ let the average weight of 2 new students be x 

⇒ according to the question 

⇒ 20 × 45 - 40 + 2x = 21 × 46 

⇒ 2x = 966 - 900 + 40 

⇒ 2x = 106

⇒ x = 53 

∴ the average weight of 2 new students is 53 kg