The sum of the ages of a daughter and her mother is 56 years. After four years, the age of the mother will be three times that of the daughter. At present their ages are
Aptitude
Problems on Ages
Difficulty: Medium
Choose an option
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A10 years, 46 years
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B12 years, 44 years
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C11 years, 45 years
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D13 years, 43 years
Answer
Correct Answer: 12 years, 44 years
Explanation
### Concept & Logic
The total sum of ages for a group increases proportionally with time. For two people, the total sum increases by $2 \times (\text{years passed})$.
Calculate the future total sum first, then distribute it according to the future ratio condition to find the individual ages.
### Step-by-Step Solution
* **Given:**
* Present sum (Daughter + Mother) = $56$ years.
* After $4$ years: Mother = $3 \times$ Daughter.
* **Calculation / Deduction:**
* In $4$ years, both the mother and the daughter will age by $4$ years.
* Total sum after $4$ years = $56 + 4 + 4 = 64$ years.
* Let the future daughter's age be $x$. The future mother's age is $3x$.
* $$x + 3x = 64$$
* $$4x = 64$$
* $$x = 16$$
* Future daughter = $16$ years. Future mother = $3(16) = 48$ years.
* To find their present ages, subtract the $4$ years back:
* Present Daughter = $16 - 4 = 12$ years.
* Present Mother = $48 - 4 = 44$ years.
### Exam Strategy & Shortcut
Use Option Elimination by adding $4$ to both numbers in the choices and checking if the mother is exactly thrice the daughter's age.
(a) $10+4=14$, $46+4=50$ (Here, $50 \neq 3 \times 14$)
(b) $12+4=16$, $44+4=48$ (Here, $48 = 3 \times 16$) - Immediate match!
You don't need to test the rest.
### Common Pitfall
Students often set up the algebraic equation directly as $x + 3x = 56$, completely forgetting to advance the total sum by $8$ years before applying the future ratio. Always synchronize your timeframes.
### Final Answer
**Therefore, the correct answer is 12 years, 44 years.**