Question

Q.11 :-The sum of ages of 5 children born at the intervals
of 3 years each is 50 years. What is the
age
of the youngest
child?​

Answer 1

Answer:

4 years

Step-by-step explanation:

let the ages of children be x,x+3,x+6,x+9,x+12 years

given sum=50

5x+30=50

5x=20

x=4

Answer 2

Answer :

4 years

Solution :

Let the age of youngest child be x years .

Then ,

The ages of the other children born at the regular interval of 3 years will be :

x + 3 , x + 6 , x + 9 , x + 12

According to the question ,

The sum of ages of these five children is 50 years .

Thus ,

=> x + (x+3) + (x+6) + (x+9) + (x+12) = 50

=> 5x + 30 = 50

=> 5x = 50 + 30

=> 5x = 20

=> x = 20/5

=> x = 4

Hence ,

Age of youngest child is 4 years .

-----------------------------------------------------------

Alternative :

Clearly ,

The given situation forms an AP as the children borned at regular interval of d = 3 .

Thus ,

Let the ages of the five children be ;

a - 2d , a - d , a , a + d , a + 2d .

Now ,

According to the question , the sum of the ages of these 5 children is 50 years .

Thus ,

=> (a - 2d) + (a - d) + a + (a + d) + (a + 2d) = 50

=> 5a = 50

=> a = 50/5

=> a = 10

Now ,

Age of youngest child

= a - 2d

= 10 - 2×3

= 10 - 6

= 4

Hence ,

Age of youngest child is 4 years .