If $(n - 1)$ is an odd number, what are the two other odd numbers nearest to it?
Aptitude
Number System
Difficulty: Easy
Choose an option
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A$n, n - 1$
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B$n, n - 2$
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C$n - 3, n + 1$
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D$n - 3, n + 5$
Answer
Correct Answer: $n - 3, n + 1$
Explanation
### Concept & Logic
Consecutive odd numbers are always separated by a constant difference of exactly 2. To find the nearest odd numbers to any given odd expression, you simply subtract 2 for the preceding odd number and add 2 for the succeeding odd number.
### Step-by-Step Solution
**Given:**
* The core expression is $(n - 1)$.
* $(n - 1)$ is an odd number.
**Calculation / Deduction:**
To find the immediately preceding odd number, subtract $2$ from the given odd number:
$$\text{Previous Odd} = (n - 1) - 2$$
$$\text{Previous Odd} = n - 3$$
To find the immediately succeeding odd number, add $2$ to the given odd number:
$$\text{Next Odd} = (n - 1) + 2$$
$$\text{Next Odd} = n + 1$$
Therefore, the two nearest odd numbers are $n - 3$ and $n + 1$.
### Exam Strategy & Shortcut
Use real numbers to bypass the algebra. Let $(n - 1) = 5$, which means $n = 6$. The nearest odd numbers to $5$ are $3$ and $7$. Now substitute $n = 6$ into the options.
Option (c) gives $6 - 3 = 3$ and $6 + 1 = 7$. This matches our numerical logic perfectly and guarantees accuracy.
### Common Pitfall
Students often misread the question and add or subtract 1 instead of 2. Doing so yields $(n - 2)$ and $n$, which represent consecutive integers (an even/odd mix), rather than consecutive *odd* numbers.
### Final Answer
Therefore, the correct answer is **$n - 3, n + 1$**.