Aptitude - Problems on Ages - Discussion

Each of the questions given below consists of a statement and / or a question and two statements numbered I and II given below it. You have to decide whether the data provided in the statement(s) is / are sufficient to answer the given question. Read the both statements and

  • Give answer (A) if the data in Statement I alone are sufficient to answer the question, while the data in Statement II alone are not sufficient to answer the question.
  • Give answer (B) if the data in Statement II alone are sufficient to answer the question, while the data in Statement I alone are not sufficient to answer the question.
  • Give answer (C) if the data either in Statement I or in Statement II alone are sufficient to answer the question.
  • Give answer (D) if the data even in both Statements I and II together are not sufficient to answer the question.
  • Give answer(E) if the data in both Statements I and II together are necessary to answer the question.

1. 

What is Sonia's present age?

I. 

Sonia's present age is five times Deepak's present age.

 II. 

Five years ago her age was twenty-five times Deepak's age at that time.

[A]. I alone sufficient while II alone not sufficient to answer
[B]. II alone sufficient while I alone not sufficient to answer
[C]. Either I or II alone sufficient to answer
[D]. Both I and II are not sufficient to answer
[E]. Both I and II are necessary to answer

Answer: Option E

Explanation:

 I. S = 5D    D = S ....(i)
5

II. S - 5 = 25 (D - 5)    S = 25D - 120 ....(ii)

Using (i) in (ii), we get S = 25 x S - 120
5

4S = 120.

S = 30.

Thus, I and II both together give the answer. So, correct answer is (E).


Geetha said: (Apr 30, 2012)  
I can't understand this.

Can anyone explain this in detail.

Deb said: (Aug 24, 2012)  
I don't understand this method please another method give and help me.

Palak said: (Oct 4, 2012)  
Geeta and deb-in 1st sonia's(S) age is 5 time the deepak(D) present age i.e S=5D OR D=S/5
in 2nd equation,5 years ago her age was 25 times the deepak at that time,i.e we deduce ages for 5 yrs ago i.e -5 or S-5 IS 25(D-5)as deepak age is also reduce by 5 from present age.on solving the equation comes S=25D-120.on putting value of D from first eqnt into 2nd we can get S i.e 30

Santosh Patil said: (Jan 8, 2016)  
II. S-5 = 25 (D-5) S = 25D - 120......(ii)

25*d = 25d.... & 25*5= 125 ok then 120 is what?

Rajat Jimmy said: (Feb 20, 2016)  
Solution is correct, i.e. 20.

If you related bit 1 and bit 2, then solution is 30.

But in data sufficiency, our main approach is to get solution thru individually bit no. So in this case solution 30 violates.

Balakumar said: (Sep 21, 2016)  
S = 5D.
D = S/5 Eq -> 1.

Then S - 5 = 25(D - 5).
S = 25D - 120 Eq -> 2.

In that Eq 1, D value substitute in Eq 2.

Then S = 25 * (S/5) - 120.
Then 5 IS SUBSTITUTE TO (S & 120).
Then 5S = 25S - 600.
25S - 5S = 600.
20S = 600.
S = 600/20.
S = 30.

Ratz said: (Oct 13, 2016)  
I really don't understand this. Please help me.

Amrish said: (Oct 14, 2016)  
According to I st statement.

Let D's age is X year then S's age is 5X year.
According to II.
=> 5 year ago,
S's age was 5X - 5 & D's age was X - 5.

But it say that it 5 yr ago S's age was 25 times of D's age at that time. So,
5X - 5 = 25(X - 5)
20X = 120; X = 6.

Now we can find age of S, D.

S = 5 * 6 = 30yr.
D = 6yr.

So, both statement are necessary.

Bharathi said: (Dec 6, 2017)  
Could anyone please explain clearly?

Raunak said: (Jul 27, 2018)  
Could anyone please explain clearly?

Shubham said: (Feb 18, 2019)  
s=d5 then let s value =d5.

then put in (ii) s=25d-120,
d5=25d-120,
120=25d-5d,
120=20d ......then d=6 and s=30.

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