The average weight of 30 students in a class is 60 kg. If the weight of the class teacher is included, the average increases by 0.5 kg. The weight (in kg) of the teacher is:
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 75.5.
Total weight of the 30 students = 60 × 30 = 1800 kg
New average weight = 60 + 0.5 = 60.5 kg
New total weight = 60.5 × 31 = 1875.5 kg
Weight of teacher = 1875.5 - 1800 = 75.5 kg