CMA Foundation · Fundamentals of Business Mathematics and Statistics · Indices and Logarithms
The value of log 25 + log 4 - log 1 (all common logarithms, base 10) is:
The value is 2. By the product law, log 25 plus log 4 equals log 100, which is 2 in base 10. Since the logarithm of 1 is zero, subtracting it leaves the answer unchanged at 2.
- A1
- B2Correct
- C0
- D3
Explanation
log 25 + log 4 = log 100 = 2 by the product law. log 1 = 0, so subtracting it changes nothing. The result is 2. Taking log 1 as 1 would wrongly give 1.
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