Question

Choose the correct answer from the alternatives given :
The average weight of 40 students is 45 kg. If the teacher is included and one student is excluded, the average weight increases by 1 kg. If the weight of excluded student is 40 kg, the weight of the teacher is:

• A. 40 kg
• B. 35 kg
• C. 80 kg
• D. 75 kg

Answer 1

The correct option is C 80 kg

Total weight of 40 students = 45 $\times$ 40 = 1,800 kg

After excluding one students remaining weight =(1,800 - 40) = 1,760 kg

Total weight when teacher included = 46 $\times$ 40 = 1,840

Weight of the teacher included = (1,840 - 1,760) = 80 kg.