Question

the average age of the first three children in a class is 13.5 years is the sum of the ages of the first two children is 25 years then what is the age of the third child​

Answer 1

The average of the first three children of the class is given to be 13.5 years

Also, the sum of first two children is 25 years

We have to find the age of the third child

Let the age of the third child be x

Then, the sum of all three ages = 25 + x

number of children = 3

Average = sum of ages/number of children

     13.5 = (25 + x) / 3

40.5 = 25 + x

    x = 40.5 - 25

   x = 15.5

Hence, the age of the third child will be 15.5 years