The average weight of 20 students is 25 kg. By the admission of new student the average weight is reduced to 24.8 Kg. The weight of new student is :

The average weight of 20 students is 25 kg. By the admission of new student the average weight is reduced to 24.8 Kg. The weight of new student is :
1). 15 Kg
2). 20.8 Kg
3). 29 Kg
4). 22 Kg

We know that, Average weight = (Sum of weight of all students)/(Total no. of students)

Initially, total number of students = 20, and Average weight = 25 Kg

∴ Sum of weight of all students initially = 20 × 25

= 500 Kg

Let the weight of new student be X Kg. Then,

⇒ New sum of weight of all students = (500 + X) Kg

Given: Average weight after entry of new student = 24.8 Kg

$(\therefore 24.8 = \frac{{500 + X}}{{20 + 1}})$

⇒ X = 20.8 kg

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