A, B, C, D and E are five consecutive odd numbers. The sum of A and C is $146$. What is the value of E?
Aptitude
Problems on Numbers
Difficulty: Easy
Choose an option
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A71
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B75
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C79
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D81
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ENone of these
Answer
Correct Answer: 79
Explanation
### Concept & Logic
Consecutive odd numbers always have a common difference of $2$. By defining the first term, the rest follow predictably.
$$A = x, B = x+2, C = x+4, D = x+6, E = x+8$$
### Step-by-Step Solution
* **Given:** We have five consecutive odd numbers: $A$, $B$, $C$, $D$, and $E$.
* **Given:** The sum of $A$ and $C$ is $146$.
* Substitute the algebraic expressions for $A$ and $C$ into the equation:
$$x + (x + 4) = 146$$
* Combine like terms:
$$2x + 4 = 146$$
* Isolate the variable term:
$$2x = 142$$
* Divide to find the value of the first odd number ($A$):
$$x = 71$$
* We need to find the value of $E$, which is $x + 8$:
$$E = 71 + 8 = 79$$
### Exam Strategy & Shortcut
Because consecutive odd numbers form an Arithmetic Progression (AP), the middle term between any two symmetric terms is their average. The number exactly between $A$ and $C$ is $B$.
Therefore, $B$ is the average of $A$ and $C$: $B = \frac{146}{2} = 73$.
Since the sequence is $A, B, C, D, E$ with a difference of $2$, you can just count up from $B$:
$B = 73 \Rightarrow C = 75 \Rightarrow D = 77 \Rightarrow E = 79$. This skips the formal algebra entirely.
### Common Pitfall
A frequent mistake is solving for $x$ (getting $71$) and immediately selecting option (a) without re-reading the final question. The problem asks for the value of $E$, not $A$. Always underline the final target variable in the question.
### Final Answer
**Therefore, the correct answer is 79.**