Aptitude - Problems on Ages - Discussion

Can you solve the problem accurately when the father's age is an odd number?

Son's age would always be half of father's age no matter what the father age is !

Because let say son age is 'x' now. When son born father age is also 'x'. So when son grew up and reach 'x', now father would be 2x.

So to find son age just divide fathers age by 2 (2x / 2 = x (son age) ).

Simple example: let say father age is 40.

0 x 20.
Son = <---------------->.
0 x 20 x 40.
Father= <-----------------><--------------->.

Then son ages - 5 = answer.

At present:
Age of son = x.
Age of father = 38.

At birth time of son:
Age of son = 0
Age of father = x.

As father grew son will also grow.
x - 0 = 38 - x

Think like person started at the same time and same speed but from the different location. Distance travelled by both will be same.

How 38 - x = x? Pease explain me.

Let the son's present age be x years.

Then, (38 - x) = x -> Why 'x' is subtracted from 38?

2x = 38 -> how 2x = 38 its not mentioned in the question?

"I was as old as you are at the present at the time of your birth" means that at the time of son birth father age was equal to present son age. So father age is now double of son age. Father's age now 38 year.

If son age is x then father's age = 2x.

Given that father's age = 38.

So, 2x = 38.

=> x = 19.

5 year back is x-5.

i.e 19-5 = 14.

Father said "I was as old as you are at the present at the time of your birth" means that;

When son born that time age of the father is equal to the present age of his son.

The present age of his son = x.
Then father age = 2x at the current time.

So, x = 38/2 = 19.

Before 5 years = 19 - 5 = 14.

14 is the answer.

How did the relation 38 - x = x arise? Explain it.

It means father's age at the time of his son's birth is equal to son's age at present.

If we take sons age at present as "x" father's age at his son's birth is also "x".

So, 2x = 38.

x = 19.

1. If at the time of father's age @15 years, his son was born, at that time son age is @1 year.

If father come into age @30 years, his son age is @15 years.

2. If at the time of father's age @20 years, his son was born, at that time son age is @1 year.

If father come into age @40 years, his son age is @20 years.

3. If at the time of father's age @19 years, his son was born, at that time son age is @1 year.

If father come into age @38 years, his son age is @19 years.

Finally that 19 years is present age of son.

But they are asking 5 years ago so, 19 years - 5 years = 14 years.