Question

1. Three years ago, the average age of
five members of a family was 17 years.
If a child get born, the average age
remains same even at the present day.
What will be the age of that child?​

Answer 1

Answer:

The age of child will be 2 years

Step-by-step explanation:

Given,

• Average age of 5 people( 3 years ago ) = 17
• Average age of 6 people ( Present ) = 17

Since,

Average age of 5 people( 3 years ago ) = 17

Hence,

Total age of 5 people (3 years ago ) = 17 × 5

= 85

Total age of 5 people at present = 85 + (5×3)

= 100

A/Q

Average age of 6 people = 17

⇒ Total age of 6 people = 17×6

= 102

Since,

Total age of 5 people at present = 100

THEREFORE

Child age = Total age of family - Total age of 5 members

= 102 - 100

= 2

HOPE IT HELPS YOU PLEASE MARK AS BRAINLIEST

Answer 2

Answer:

Age of child = 2

Step-by-step explanation:

Given :

• Average age of 5 members of a family 3years ago was 17

• If a new child born, the average is also 17.

To find :

• Age of the child

To find Average :

${\boxed{\frak{average \: = \frac{sum \: of \: ages \: of \: members}{total \:no.of \: members } }}}$

Solution :

Let's find the total sum of ages of members in this family.

Let the sum of ages of members be x,

• 3 years ago, avg of 5 members = 17

• ( x/5-3 = 17)

$\to \sf \: \frac{x}{5} - 3 = 17 \\ \\ \to \sf \: \frac{x}{5} - \frac{3}{1} = 17 (cross \: multiply) \\ \\ \sf\to \: \frac{1x - 15}{5} = 17 \\ \\ \to\sf \: \frac{x - 15}{5} = 17(cross \: multipy) \\ \\ \sf \to \frac{x - 15}{5} = \frac{17}{1} \\ \\ \sf\to \: 1(x - 15) = 17 \times 5 \\ \\ \sf\to \: x - 15 = 85 \\ \\ \sf\to \: x = 85 + 15 \\ \\ \to\bf \: x = 100$

So, Total sum of ages of members = 100

Let's find the age of child by this ; nd take age of child be y

• the total members = 6

• sum of ages of 5 members( before 3 years) = 100

• The average still 17

• 100+y/6 = 17

$\sf \to \: \frac{100 + y}{6} = 17 \\ \\ \sf \to \: \frac{100 + y}{6} = \frac{17}{1} (cross \: multiply) \\ \\ \to\sf \: 1(100 + y) = 17 \times 6 \\ \\ \sf \to \: 100 + y = 102 \\ \\ \sf \to \: y = 102 - 100 \\ \\ \bf\to \: y = 2$

∴ Age of child = 2

Let's Verifiy both :

1 ) Sum of ages of 5 members before 3 years ;

( look the above equations )

$\to \sf \: \frac{ x}{5} - 3 = 17 \\ \\ \to \sf \: \frac{100}{5} - 3 = 17 \\ \\ \to \sf \: 20 - 3 = 17 \\ \\ \sf \to \: 17 = 17$

∴ LHS = RHS

2 ) Age of child ;

$\sf\to \: \frac{100 + y}{6} = 17 \\ \\ \sf \to \: \frac{100 + 2}{6} = 17 \\ \\ \sf \to \: \frac{102}{6} = 17 \\ \\ \sf \to \: 17 = 17$

∴ LHS = RHS

Thus Solved !!