Given log<sub>10</sub>2 = 0.3010 and log<sub>10</sub>3 = 0.4771, evaluate log<sub>5</sub>512.
Aptitude
Logarithm
Difficulty: Medium
Choose an option
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A3.700
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B3.876
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C3.909
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D4.000
Answer
Correct Answer: 3.876
Explanation
Concept / Approach
- Use change of base: log5512 = log10512 / log105.
Step-by-step calculationlog10512 = log10(29) = 9 × 0.3010 = 2.709log105 = 1 − log102 = 1 − 0.3010 = 0.6990log5512 = 2.709 / 0.6990 = 3.876 (approx.)
Verification53 = 125 < 512 < 625 = 54 ⇒ answer between 3 and 4, consistent.