Aptitude - Problems on Ages - Discussion

Nice Thanks @Shriram.

Let present age of son =x.
At the time birth son = 0 and father = x.
Now, son = x & father= 2x
So 2x= 38
=} x = 19.
5 years ago son was 19-5= 14 years.

@Siva.

In the question, "I was as old as you are at the present at the time of your birth"
Son's present age = Father age when son was born.

In the question father age=38, let son age be 'x'.
Father present age - son present age = father age when son was born ( i.e., son present age)
38 - x = x.
38 = 2x.
x = 19.
Sons age 5 years back x-5 = 19-5 ==>x = 14.

Fathers current age is 38, since we don't know son's age we will consider his age as X. So now,

Fathers current age is 38--------------------(eqn 1).

Sons current age is X.

When his son was born then his fathers current age should be X(because "I was as old as you are at the present at the time of your birth")(sons present age is X, so when father told this dialogue then at that time his age should also be X).

So at the birth sons age is 0 and his fathers age is X.
During Birth:

Son's current age = 0.
Fathers current age = X.

Now son has grown upto X years so father will also grow up to X years, so Sons age will be 0+X and fathers age will be X+X.

Fathers age =X+X=2X-----------------------(eqn 2),

Equating (1)&(2),

2X = 38.

X = 19.

Sons current age is 19 and 5 years back he will be 19-5 = 14.

Please solve this.

The present age of Geetha is 5 years more than the present age of his brother Mahesh. The present age of their father is twice the sum of their ages. At the time of Mahesh's birth, his father age was 8 times of the age of Geetha.

Find their present ages.

How did we know that the father's age is now double of son's age?

As @Naseem has mentioned. How can the mere mention of a father proclaiming that "he was the same age as the present age of the son, at the time of son's birth". Indicate or point out that the father's present age is double of the son, or that the son's age is half of the father. This is the greatest unsolved mystery of this question that has been in my mind for years.

These can be solved by option elimination method we have to see by option which no will be divided by 38 in option 19*2=38. Now subtract by 5 because it has told 5 years ago 19-5=14.

(38-X)=X so X taking other side negative becmes positive X.so 2X
38-X=x
38=2x
x=19

Thanks @Geet.

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