Question

The average age of the first three children in a class is 13.5 years. If the sum
the ages of the first two children is 25 years, then what is the age of the
third child?
A) 15.5 years
(B) 13.2 years
(C) 12.8 years
(D) 12 5 years​

Answer 1

Answer:

i think A) 15.5 years

hope it will help you

Answer 2

Answer :-

15.5 years

Explanation :-

Given :

Average age of the first three children => 13.5 years

Total sum ages of the first two children => 25 years.

Note :

The average is the age that we get after dividing the total number of ages by the number of people in the group. For example, there are five friends of different ages, first friend age is 14, second friend age is 16 and the third friend age is 17. Here the average age of these three friend age is 15.6 years.

[(14 + 16+ 17)/3 = 15.6]

Total sum age means the total age. For example, a child age is 13 year and his mother age is 34. Here their total sum age is 47 years.

[13 + 34 = 47]

To Find :

We have to find the age the third child.

Solution :

The average age of the first three students is 13.5 years.

Therefore, the total sum age of three students = 3 × 13.5

⇒ 40.5 years

Total sum age of two students = 25years

If we will subtract the sum age of first three with first two then we will get the age of the third child.

Age of third child,

$\sf{}First\ three\ children\ total\ sum\ age-First\ two\ children\ total\ sum\ age$

$\sf{}:\implies 40.5-25$

$\sf{}\therefore 15.5\ years$

Therefore,15.5 years is the age of third child.

Hence, option (A) is correct