Question

average age of a group of 10 students is 12 yr.if 5 new students join them.then the average age of new group increase by 1 yr. fhen the average age of new grp is?​

Answer 1

Answer:

Average age = sum of age of all students/ toral no. Of Student

Hence, 15 = sum of age of all ten students/10

=> Sum of age of all students = 15* 10= 150

Acc to ques. Now total students = 10+5= 15

Average age = 16

Again, average age = sum of age / total no. Of students

16 = sum of ages of fifteen students/ 15

Sum of age of 15 students = 16*15 =240

Hence sum of age of 5 new students = 240 - 150 = 90

Answer 2

so if you are asking for the 5 student group

what we do is to :

average age of 10 students = 12

sum of the age of 10 students 10 x 12

= 120

5 more students join new average increases by 1 = 12+1 =  13

(average age of 15 students is =  13yr)

sum of the age of 15 students = 15 x 13

= 195yrs

now subtract old sum from  new some

= 195 - 120 = 75yrs

sum of age of 5 students

now to find average we do this :

sum of students/number of students

all right so we know the sum of age of 5 students

So,

75/5 = 15yr

the average year of the group of 5 students id 15yrs

Hey mate both answers

(average age of 15 students ) and (average age of 5 students are given)

I was confused pick what you want

Hope it helps you

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