CA Foundation · Quantitative Aptitude · Ratio and Proportion, Indices and Logarithms
Using change of base, log₂₅ 125 equals:
The value is 3/2. Writing 125 as 5³ and 25 as 5², the change of base gives 3 log 5 divided by 2 log 5, which simplifies to 3/2.
- A3/2Correct
- B2/3
- C5
- D3
Explanation
log₂₅ 125 = log 5³ / log 5² = 3 log5 / 2 log5 = 3/2. Option 2/3 inverts the ratio, which is the reciprocal log₁₂₅ 25.
Did you get it right without looking?
One question tells you little. A timed set on Ratio and Proportion, Indices and Logarithms shows your real accuracy, how long you take and where you lose marks.
More Ratio and Proportion, Indices and Logarithms questions
- If (3x + 2y)/(3x − 2y) = 5/3, then the ratio x : y is:
- The mean proportional between 4 and 25 is:
- If (a + b)/(a − b) = 9/5 and a, b are positive, then the value of a² : b² is:
- If log₁₀ 2 = 0.3010, the number of digits in 2⁴⁰ is:
- If log₃ 5 = a, then log₉ 25 expressed in terms of a is:
- A variable Y is inversely proportional to the square of variable X. When X = 2, Y = 18. What will be the value of Y when X = 3?