If $a, b, c, \dots, x, y, z$ are $26$ natural numbers, then the value of $(x - a)(x - b)(x - c) \dots (x - y)(x - z)$ is
Aptitude
Simplification
Difficulty: Easy
Choose an option
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A0
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B1
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C13
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D26
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ENone of these
Answer
Correct Answer: 0
Explanation
Concept & Logic
This is a classic logical puzzle disguised as an algebra problem. It tests your ability to recognize patterns within a sequence rather than performing actual mathematical calculations. The key is identifying a specific term within the long product chain that forces the entire expression to evaluate to a constant.
Step-by-Step Solution
* Given expression:
$$ (x - a)(x - b)(x - c) \dots (x - y)(x - z) $$
* Step 1: Understand the pattern of the sequence. The first term in each bracket is always the variable $x$. The second term iterates through the alphabet from $a$ to $z$.
* Step 2: Trace the sequence mentally. It goes $(x - a)$, $(x - b)$, $(x - c)$, and so on. Since it iterates through the entire alphabet, it must eventually reach the letter $x$ as the second term.
* Step 3: Identify the critical bracket. At the 24th position in the sequence, the bracket will be:
$$ (x - x) $$
* Step 4: Evaluate the critical bracket.
$$ (x - x) = 0 $$
* Step 5: Apply the zero product property. Any number multiplied by $0$ results in $0$.
$$ \text{(Product of previous terms)} \times 0 \times \text{(Product of remaining terms)} = 0 $$
Exam Strategy & Shortcut
**Look for the Zero Term:**
Whenever you see a long sequential product, especially one involving the alphabet or a long string of integers, immediately scan for a term that evaluates to zero. In alphanumeric sequences, look for self-subtraction like $(x - x)$ or $(n - n)$. The moment you realize $(x - x)$ is part of the sequence, the answer is instantly $0$ without any further thought.
Common Pitfall
The main pitfall is panic. Students see an infinite-looking algebra string with 26 unknown variables and assume it requires complex polynomial expansion or advanced theorems, wasting time on a problem designed to be solved in two seconds via logical deduction.
Final Answer
**Therefore, the correct answer is 0.**