Aptitude - Problems on Ages - Discussion

4X+8 = (X+8) * 2.5,
4X+8 = 2.5X + 20,
1.5X = 12,
X = 8
If X=8, Then Father age is 32 (Four times X)
Now, After Eight years Ronith age is 16, Father age is 40 which is 2.5 times of Ronith age.

Later, After further Eight years Ronith age is 24, Father age is 48.

That means Father age is Two times of Ronith age.

So Answer is Option A) 2 times.

Yes, I agree with you @Janarthanan.

@All.

Here is the trick to solve this;
Father : Son.
4 : 1.
And +8 years, according to the question, it becomes 5/2.
So,
5 : 2.
And again 8 years. So in the above ration there is 1 increment in 8 year it means for the next 8 year 1 more increament then we get.
6 : 3 which is = 2(Ans).

How to add 8 more in a 16 ratio?

Very clear, thanks all for explaining the answer.

Present ages F : S = 4:1(because father is 3 times more than son which is 4-1 =3)
Father = 4R.
Son = R.

After 8 years
F: S = 2.5 : 1.

(4R + 8)(R+8) = 2.5
4R + 8 = 2.5(R + 8),
4R + 8 = 2.5R + 20,
4R - 2.5R = 20 - 8.
1.5R = 12.
R=12/1.5 = 8.
If R is 8 then 4R is 4(8)= 32, that is, father's age after 8 years.
So, after 16(that is, after 8 years + after 8 years).
F = 32 + 16 = 48.
S = 8 + 16 = 24.
F:S = 48:24 = 2:1.
That is Father's age 2 times more than son after another 8 years.

4x + 8 = 2.5x + 20.
1.5x = 12,
x = 12/1.5
x = 8.
24/48 = 1/2.

@All.
Simply;
Ronith's present age = x.
Father's age=3 times more than Ronith's age.
So, x + 3x = 4x.
So, after 8 years, 4x + 8 = 5/2(x+8) by doing the calculation we will x = 8.
Further 8 years:
Now we are in the present stage, so they have asked for a further 8 years,
So, a further 8 years and an additional 8 years =16 years.
=> 4x + 16/x + 16+2.

@All.

My doubt is; in the question, it is given "Father has aged 3times the son" then how father's age will be x + 3x = 4x? If 4x is father age then it will become wrong. right?

Ex. Let son age be 2 years, father age will be 8years (4x, as given in explanation). Then how it will be correct?

Anyone, explain this to me.

He would be 2 (1/2) times of Ronit's age.

2 1/2 which is a mixed fraction. So it is written as [ (2*2) +1]/2 = 5/2.