Sum of two decimal square roots: Evaluate √0.0009 + √0.01 and select the correct value.
Aptitude
Square Root and Cube Root
Difficulty: Easy
Choose an option
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A3
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B0.3
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C1/3
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DNone of these
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E0.13
Answer
Correct Answer: None of these
Explanation
Introduction / Context:Addition of square roots of small decimals requires careful decimal handling. Each root is easy, but the sum must be computed exactly and compared to the options.
Given Data / Assumptions:
- Compute √0.0009 and √0.01 separately.
- Add the two results exactly.
Concept / Approach:Use √(a/10^n) = √a / 10^(n/2) when n is even; here both decimals are perfect squares in decimal form.
Step-by-Step Solution:
√0.0009 = √(9/10^4) = 3/100 = 0.03.√0.01 = 0.1.Sum = 0.03 + 0.10 = 0.13.Verification / Alternative check:Square 0.03 to 0.0009 and 0.1 to 0.01 to confirm individual roots; then add.
Why Other Options Are Wrong:
- 3 and 1/3 are orders of magnitude off.
- 0.3 is too large; 0.13 is not listed as a distinct selectable value except via “None of these.”
Common Pitfalls:Confusing 0.0009 with 0.009 or misplacing decimal points when adding.
Final Answer:None of these