CA Foundation · Quantitative Aptitude · Ratio and Proportion, Indices and Logarithms
The value of log₅ 125 + log₂ 32 − log₁₀ 1000 is:
The value is 5. Since 5³ = 125, 2⁵ = 32 and 10³ = 1000, the three logarithms equal 3, 5 and 3 respectively. Adding the first two and subtracting the third gives 3 + 5 − 3 = 5.
- A5Correct
- B8
- C3
- D11
Explanation
log₅125 = 3 because 5³ = 125. log₂32 = 5 because 2⁵ = 32. log₁₀1000 = 3. So the value is 3 + 5 − 3 = 5. Option 11 results from adding all three terms instead of subtracting the last.
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