What is the greater of the two numbers whose product is 1092 and the sum of the two numbers exceeds their difference by 42?
Aptitude
Problems on Numbers
Difficulty: Medium
Choose an option
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A44
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B48
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C52
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D54
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ENone of these
Answer
Correct Answer: 52
Explanation
## Concept & Logic
Translating a word problem into algebraic expressions is key here. The phrase "sum exceeds difference by" can be translated into a direct equation. Interestingly, the variables representing the "greater" number will cancel out in this translation, instantly revealing the smaller number.
$$ (x + y) - (x - y) = \text{Excess Amount} $$
## Step-by-Step Solution
* **Given:** Let the two numbers be $x$ and $y$, where $x > y$. The product $x \times y = 1092$.
* **Calculation / Deduction:**
* The sum is $(x + y)$. The difference is $(x - y)$.
* Set up the equation based on the condition "sum exceeds difference by 42":
* $(x + y) - (x - y) = 42$
* Simplify the left side:
* $x + y - x + y = 42$
* $2y = 42$
* $y = 21$
* We now know the smaller number is $21$. Use the product to find the greater number ($x$):
* $x \times 21 = 1092$
* $x = \frac{1092}{21}$
* $x = 52$
## Exam Strategy & Shortcut
**Logical Deduction:** Realize that the difference between the sum $(A+B)$ and the difference $(A-B)$ of two numbers is ALWAYS simply twice the smaller number ($2B$). Therefore, if the difference is $42$, the smaller number is instantly $21$. Divide $1092$ by $21$ to get $52$. To quickly divide $1092$ by $21$, look at the unit digit: $1 \times \text{what} = 2$? It must end in $2$. Look at the options; $52$ is the only logical choice that works ($20 \times 50 = 1000$).
## Common Pitfall
A major pitfall is trying to set up complex quadratic equations using substitution before simplifying the "sum exceeds difference" clause. Always simplify your linear conditions completely before plugging them into a product condition.
## Final Answer
**Therefore, the correct answer is 52.**