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Question

The ages of two persons differ by 15 years. If 5 years ago, the age of the older person was twice that of the younger one, then their present ages (in years) are:

This question was previously asked in
RRB NTPC 2019 CBT 1 Question Paper (8-Mar-2021) (Shift 2)
The correct answer is
35, 20

Age Difference Problem Explained

This problem involves finding the current ages of two people based on their age difference and a relationship between their ages in the past.

Setting Up the Equations

Let the present age of the older person be $x$ years and the present age of the younger person be $y$ years.

From the problem statement:

  • The ages differ by 15 years: $x - y = 15$. (Equation 1)
  • 5 years ago, the older person's age was $x - 5$ and the younger person's age was $y - 5$.
  • The older person's age 5 years ago was twice the younger one's age: $x - 5 = 2(y - 5)$. (Equation 2)

Solving for Present Ages

We can solve these two equations simultaneously.

  1. Express $x$ in terms of $y$: From Equation 1, $x = y + 15$.
  2. Substitute into Equation 2: Replace $x$ in Equation 2 with $(y + 15)$. $(y + 15) - 5 = 2(y - 5)$
  3. Simplify and solve for $y$: $y + 10 = 2y - 10$ $10 + 10 = 2y - y$ $20 = y$ So, the younger person's present age is 20 years.
  4. Calculate $x$: Substitute $y = 20$ back into Equation 1 (or the expression for $x$). $x = y + 15 = 20 + 15 = 35$ So, the older person's present age is 35 years.

Conclusion

The present ages of the two persons are 35 years and 20 years.

Verification:

  • Age difference: $35 - 20 = 15$ years. (Correct)
  • 5 years ago: Older was $35 - 5 = 30$, Younger was $20 - 5 = 15$.
  • $30 = 2 \times 15$. (Correct)

The calculated ages match the conditions given in the problem.

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Similar Questions

  1. Narendra's mother is four times as old as Narendra. Four years ago, his mother was six times as old as Narendra was. What are their Present ages?
  2. A mother is now three times as old as her daughter. 5 years ago, she was four times as old as her daughter. What is the current age of the daughter?
  3. If 3 times a mother's present age is 24 years more than 9 times her daughter's present age, and 4 times the daughter's present age is 2 years less than the mother's present age, then what is the difference (in years) between the ages of the mother and the daughter?
  4. John is twice as old as Jean. After 3 years, the sum of their ages will be 66 years. What are the present ages of Jean and John, respectively?
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Important Questions from Problems on Age

  1. The age of Dr. Pandey is four times the age of his son. After 10 years, the age of Dr. Pandey will be twice the age of his son. The present age of Dr. Pandey's son is?

  2. Three years ago, the average age of a family of six members was 19 years. Since then, a boy has been born, and the average age of the family is the same today as it was three years ago. What is the age of the boy?

  3. Amita is 2 years older than her friend Amrita. Amita's father is twice as old as Amita, and Amrita is twice as old as her sister. The ages of Amita's father and Amrita's sister differ by 43 years. The sum of the ages (in years) of Amita and Amrita is:

  4. Narendra's mother is four times as old as Narendra. Four years ago, his mother was six times as old as Narendra was. What are their Present ages?
  5. A mother is now three times as old as her daughter. 5 years ago, she was four times as old as her daughter. What is the current age of the daughter?
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