Question

Two years ago,the average age of a family of 5 members is 16 years.After a baby is born,the average age of a family is the same today.Find the present age of the baby.​

Answer 1

Step-by-step explanation:

Total age of the family three years ago = 17 x 5 = 85 years.

Let the present age of the child be x years.

Present total age of the family = 85 + 5 x 3 + x = (100 + x) years.

Given

6

100+x

=17

⇒100+x=102⇒x=2 years

Answer 2

Given:

Two years ago, the average age of a family of 5 members is 16 years. After a baby is born, the average age of a family is the same today.

To find:

The present age of the baby.

Solution:

The present age of the baby is 6 years.

To answer this question, we will follow the following steps:

As given, we have,

Two years ago, the average of the family of 5 members = 16 years.

So,

The sum of ages of 5 members before two years

$= 16 \times 5 = 80 \: years$

The sum of ages of 5 family members after 2 years i.e. at present

$= 80 + (5\times 2) = 90 \: years$

Now,

Let the present age of the baby be x years.

At present, the average age is the same = 16 years.

So,

The number of family members at present = 6

The sum of presents ages of family members = (90 + x) years

Thus,

$\frac{90 + x}{6} = 16$

$90 + x = 96$

$x = 6 \: years$

Hence, the present age of the baby is 6 years.