Question

The average age of 25 students in a class is 12 years. 15 students whose average age is 10 years joined them. What is the present average age.

Answer 1

Hey.

Here is the answer.

Present average age

= sum of ages of all students / no. of students

or, sum of ages of all students

= 25×12 + 15×10

= 300 + 150

= 450

Total no. of students = 25 + 15 = 40

So, present average age = 450/40 years

= 11.25 years

Thanks .

Answer 2

Hi Friend !!!

Here is ur answer !!!

Average of 25 students = 12

Sum = 12×25

= 300


Average of 15 students = 10

Sum = 10×15

= 150

Total sum = 150+300

= 450

Mean = 450 / 15+25

= 450/40

= 11.25


Hope it helps u : )