Important Formulas on “Problems on Ages” :
1. If the current age is x, then n times the age is nx.
2. If the current age is x, then age n years later/hence = x + n.
3. If the current age is x, then age n years ago = x – n.
4. The ages in a ratio a : b will be ax and bx.
5. If the current age is x, then 1/n of the age is x/n
Example
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
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- 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.
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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. |
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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 |
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Answer: Option E
Explanation:
I. S = 5D D = | S | ….(i) |
5 |
II. S – 5 = 25 (D – 5)
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S = 25D – 120 ….(ii)
Using (i) in (ii), we get S = |  | 25 x | S |  | - 120 |
5 |
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4S = 120.
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S = 30.
Thus, I and II both together give the answer. So, correct answer is (E).
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