Question

The mean age of 5 children of a family is 12 years. If four of them are respectively
6,11,13 and 16 years. Find the age of the fifth child.

Answer 1

Hint: To solve the question we need to find out the total age of $5$ children of a family after which we have to subtract the age of the $4$ children and the remaining age will be the age of the fifth children.

Complete step by step answer:
It is stated in the question that the average age of $5$ children is $12$ years.
Therefore the total age of five children $ = 12 \times 5 = 60$ years
Now we need to subtract the given ages of the four children from the total age of the five children $ = 60 - 16 - 13 - 11 - 6 = 14$ years
Hence we get the age of the fifth child.

Therefore, the age of the fifth child $ = 14$ years.

Note:
This sum can be easily solved by applying the techniques of simple arithmetic questions. Besides this, there is another method of solving this question that is by considering the age of the fifth child as $x$and forming an equation and after solving that equation we can easily find out the age of the fifth child.
The average is based on the mean value that is equivalent to the total between the sum of the number of values given in the set and the total number of values in the set.
The formula of average is used in real life also in many ways. The formula for average in mathematics is
$Average = \dfrac{{{\text{sum of numbers}}}}{{{\text{Number of units}}}}$
If the average age of men or women in a category or average male height in India needs to be found out, then we can get it by adding all the values and dividing them by the number of values.