In a class, there are 39 students and their average weight is 51 kg. If we include the weight of the teacher then, the average weight becomes 51.2 kg. What is the weight of the teacher?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 59 kg.
We know that,
Average = Sum of observations/Number of observations
Now,
The average weight of 39 students = 51 kg
Total weight of 39 students = 51 × 39 = 1989
The average weight of 39 students and one teacher = 51.2 kg
Total weight of 39 students and one teacher = 51.2 × 40 = 2048
Weight of teacher = Total weight of 39 students and one teacher - Total weight of 39 students
⇒ (2048 - 1989) = 59 kg