Aptitude - Problems on Ages - Discussion

Discussion Forum : Problems on Ages - Data Sufficiency 1 (Q.No. 1)
Directions to Solve

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.

I alone sufficient while II alone not sufficient to answer
II alone sufficient while I alone not sufficient to answer
Either I or II alone sufficient to answer
Both I and II are not sufficient to answer
Both I and II are necessary to answer
Answer: Option
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).

Discussion:
14 comments Page 1 of 2.

Priya said:   3 years ago
Sonia's present age =5x, Deepak's present age=x.
Five years ago is past, that is s-5, d-5 formula.

n'times=n*x.
25 times.
Here, s=5D.
D = s/5.
s-5 = 25(D-5).
s-5 = (25 * D) - (25 * 5).
s-5 = 25D-120
D = s/5.
s = (25 * s/5)-120,
4s = 120,
s = 120÷4.
s = 30.

A.santhanalakshmi said:   4 years ago
Deepika's present age= x.
Sonia present age=5x.
5x-5=25(x-5),
5x-5=25X-125,
20x-120=0,
x=6.
Sonia's present age = 30.

Priya said:   5 years ago
Where did that 4S come from?! Please explain.

Shubham said:   5 years ago
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.

Raunak said:   6 years ago
Could anyone please explain clearly?

Bharathi said:   6 years ago
Could anyone please explain clearly?

Amrish said:   7 years ago
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.

Ratz said:   7 years ago
I really don't understand this. Please help me.

Balakumar said:   7 years ago
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.

Rajat Jimmy said:   8 years ago
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.


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