If $\sqrt{4096} = 64$, then the value of $\sqrt{40.96} + \sqrt{0.4096} + \sqrt{0.004096} + \sqrt{0.00004096}$ up to two places of decimals is
Aptitude
Square Root and Cube Root
Difficulty: Medium
Choose an option
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A7.09
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B7.10
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C7.11
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D7.12
Answer
Correct Answer: 7.11
Explanation
Concept & Logic
Evaluate a sequence of decimal square roots by applying the provided base root and dynamically adjusting the decimal places for each term before summing them.
Step-by-Step Solution
* **Given:** The core integer root is $\sqrt{4096} = 64$.
* **Calculation:** Determine the precise value of each decimal term:
* $\sqrt{40.96} = 6.4$ (2 places converts to 1 place)
* $\sqrt{0.4096} = 0.64$ (4 places converts to 2 places)
* $\sqrt{0.004096} = 0.064$ (6 places converts to 3 places)
* $\sqrt{0.00004096} = 0.0064$ (8 places converts to 4 places)
* Add the evaluated results together:
$6.4 + 0.64 + 0.064 + 0.0064 = 7.1104$
* The question asks for the answer up to two decimal places:
$7.1104 \approx 7.11$
Exam Strategy & Shortcut
To save time, only sum the terms that affect the first two decimal places. $6.4 + 0.64 + 0.064 = 7.104$. We know the final term ($0.0064$) will push this to $7.1104$. Rounding to two decimal places yields $7.11$.
Common Pitfall
Failing to properly carry over values during decimal addition, or rounding prematurely before all necessary terms have been combined.
Final Answer
**Therefore, the correct answer is 7.11.**