Average age of a group of 40 student is 37 years. If teacher I'd included then the average age rises by 1 , then find the age of teacher after 2 years ?

Answer 1

Hi!

First, let's make sure we understand the parts of the question that we're given:

We know the average age of a group of 40 students, which is 37 years. Since average age = total sum of ages of the 40 people/number of people, we know that the total sum of ages of the 40 students is 37 * 40 = 1480. So, if we were to add up all of the ages of the 40 students, we would get 1480 years.

Now, by adding the teacher to the group, we get a group size of 41 people and we know that the average of this group of 41 people is greater than the original average by 1, so the new average of the 41 people is 37 + 1 = 38 years. Using the same definition of average as seen above, we know that the total sum of ages of the 41 people is 38 * 41 = 1558 years.

The only difference between the group of 40 students and the group of 41 people is that the group of 41 people now includes the teacher. So, to find the age of the teacher, all we have to do is subtract the new total sum of ages (of the 40 students + teacher) by the original total sum of ages (of the 40 students). So, the teacher's age is equal to 1558 - 1480 = 78 years.

But since the question is asking for the age of the teacher AFTER 2 years (remember to always READ the question carefully), we have to add to the current age of the teacher. So, the age of the teacher after 2 years is 78 + 2 = 80 years.

Hope this helped!

Aria