Logarithms questions and answers

20 questions in 2 online tests, each with its answer and a worked solution.

Start Test 1

Logarithms: key points

Logarithms are the inverse of powers: log base b of x is the exponent to which b must be raised to get x.

  • log(a × b) = log a + log b.
  • log(a ÷ b) = log a − log b.
  • log(an) = n log a.

How to practise Logarithms

Start with the key points, then take one Logarithms test without rushing. Review every explanation, note the steps you missed and repeat the topic against the clock. APTITUDE TESTER has 20 questions in 2 tests for this topic.

  • Read the method before attempting a timed test.
  • Record mistakes by type: concept, calculation or time management.
  • Return to the hardest questions after a day and try them again.

Continue with another Quantitative topic when your accuracy is steady.

Logarithms online tests

Sample Logarithms questions

  1. 1. Find log base 10 of 100000.
    1. 8
    2. 6
    3. 7
    4. 5

    Reference: q-8074b37c-28 · Report this question

    Show answer and solution

    Answer: D. 5

    Since 10^5 = 100000, log base 10 of 100000 = 5.
  2. 2. Find log base 2 of (4 × 8).
    1. 6
    2. 2
    3. 5
    4. 8

    Reference: q-1439059c-28 · Report this question

    Show answer and solution

    Answer: C. 5

    log(a×b) = log a + log b, so the answer is 2 + 3 = 5.
  3. 3. Find log base 2 of (16 ÷ 4).
    1. 3
    2. 4
    3. 1
    4. 2

    Reference: q-859949bf-29 · Report this question

    Show answer and solution

    Answer: D. 2

    log(a÷b) = log a − log b, so the answer is 4 − 2 = 2.

See all the questions of Test 1

Logarithms: questions people ask

How many Logarithms questions are there?

There are 20 Logarithms questions in 2 tests. Each test has its own page that lists the questions with their answers and solutions.

How long does a Logarithms test take?

A test of 10 questions has a time limit of 15 minutes, which is 90 seconds a question.

Is there negative marking?

Rules vary by set. The rules screen shows the time limit, marks, any wrong-answer penalty and calculator permission before you begin. Feedback mode has no time limit or negative marking.

Can I practise Logarithms without a time limit?

Yes. Choose practice mode: there is no clock, and the answer and solution appear as soon as you select an option.