The average weight of all the students of a class is 65 kg. When the weight of a teacher is also included, the average weight increases by… — Answer & Discussion

The average weight of all the students of a class is 65 kg. When the weight of a teacher is also included, the average weight increases by 0.4 kg. If the weight of the teacher is 75 kg, how many students are there in the class?

Answer not set

Join the discussion Report an error

Discussion 1

CCommunity08 Jun 2019

Let there are ‘x’ students in the class

Total weight of x students = 65x kg

When the weight of teacher is also included,

⇒ Average weight = 65 + 0.4 = 65.4 kg

⇒ Total weight = (x + 1) × 65.4 = 65.4x + 65.4

But, the weight of teacher is 75 kg,

⇒ 65.4x + 65.4 = 65x + 75

⇒ 65.4x - 65x = 75 - 65.4

⇒ x = 9.6/0.4 = 24

∴ There are 24 students in the class