Question

The sum of 6 children born at 9 year intervals each is 159. What is the age of the 4th child?

Answer 1

Answer:

31

Step-by-step explanation:

Let the age of smallest child be 'x'

By using Arithmetic Progression(AP), we get:

a=x

n=6

d=9

sn=159

wkt: sn=(n/2)(2a+(n-1)d)

Now,

159=(6/2)(2x + 5*9)

53=2x + 45

x=4

Therefore, age of first child is 4 years

So, age of 4th child can be calculated by the formula an=a+(n-1)d

an=4+(3)9

an=31

THE AGE OF FOURTH CHILD IS 31 YRS.

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