Question

Com a entrada da Rita a classe ficou com 20 alunos a média das idades destes 20 alunos é 13,2 anos

No final da primeira semana dois alunos de 15 anos abandonaram a classe
Qual passou a ser a média

Answer 1

New avaerage if 2 students (15 year old) left = 13

Explanation:

Given:

Average age of 20 students = 13.2

Find:

New avaerage if 2 students (15 year old) left

Computtaion:

Sum of all 20 student's age = 20 x 13.2

Sum of all 20 student's age = 264

Sum of current 18 student's age = 264 - 15 - 15

Sum of current 18 student's age = 234

New avaerage if 2 students (15 year old) left = 234 / 18

New avaerage if 2 students (15 year old) left = 13