Examples on Averages 2

In this class, We discuss Examples on Averages 2

For Complete YouTube Video: Click Here

The reader should have prior knowledge of Examples of averages 1. Click Here.

Example 1:

The average of twenty-five results is 18.

The average of the first 12 is 14, and the last 12 is 17.

Find the thirteenth number.

Solution:

Thirteenth number = sum of 25 numbers – the sum of 24 numbers

An average of 25 numbers is given to find the sum of the 25 numbers.

Similarly, the average of the first 12 and last 12 is given to find the sum of the values of 24 numbers.

13th number = (18*25) – ((14*12) + (17*12)) = 78

Example 2:

The average age of a class of 39 students is 15 years.

The average increases by three months if the teacher’s age is included.

Find the age of the teacher.

Solution:

Age of teacher = Total age of students + teacher – Total age of students

Age of teacher = (15 years 3 months * 40) – (39 * 15)

= (15 1/4 * 40) – (39 *15)

= (61/4 * 40) – (39 * 15)

= 610 – 585

= 25 years