Average weight of 25 students of a class is 50 kg. If weight of class teacher is included , average is increased by 1 kg. The weight of teacher is ?

According to the question,
Average weight of 25 students = 50 kg
Sum of the weight of 25 students
= 50 × 25 = 1250 kg
If the class teacher included the average is increased by 1 kg.
? Average weight of 25 students and teacher = 51 kg
? Sum of weight
= 26 × 51
= 1326 kg
? Class teacher weight
= 1326 - 1250
= 76 kg

Alternate :
If the weight of the class teacher is included the average is increased by 1 kg.
? Total increased in weight
= 26 × 1 = 26 kg
Note :
If the weight of class teacher is same as the average weight of 25 students then there would have been no effect on average. But the weight of class teacher is more than the average of 25 students weight then average is increased by 1 kg.
? Class teacher's weight
= 50 + 26 = 76 kg