Answer: The average age of the children at the library is 7.1 years.
Explanation:
Given,
Out of 20 children, six of the children have an average age of 5 years,
Thus, the sum of the ages of 6 students = 5 × 6 = 30
( Total sum of observations = Their Average × Total numbers of the observations )
Now, remaining students = 20 - 6 = 14,
Since, the remaining children have an average age of 8 years.
Thus, the sum of the ages of 14 students = 14 × 8 = 112,
Total sum of the ages of 20 students = 30 + 112 = 142
=142/20
= 7.1 years