# Aptitude - Logarithm - Discussion

### Discussion :: Logarithm - General Questions (Q.No.7)

7.

If log10 2 = 0.3010, then log2 10 is equal to:

[A].
 699 301
[B].
 1000 301
[C]. 0.3010
[D]. 0.6990

Explanation:

 log2 10 = 1 = 1 = 10000 = 1000 . log10 2 0.301 3010 301

 Melissa Ramnauth said: (Oct 23, 2011) I do not understand how you get 10000 divided (over) 3010 giving it a result of 1000 divided (over) 301.

 Rajeev said: (Dec 8, 2011) We know that change based of log. Log2 10 written as log10 10 divided by log10 2. We have a value of log10 2. So simple calculation.

 Arun said: (Feb 20, 2014) log(a) X =log X/log a using this formula we can solve.. log(10) 2 = 0.3010. Using that formula we can write log 2/log 10=0.3010. So take reciprocal log 10/log 2 = 1/0.3010...use the first line formula log(10) 2 = log 10/log 2 [i.e.log(a) X = log X/log a]=1/0.3010 = 1/3*10power of -4 = 10000/3010 = 1000/301.

 Puneet said: (Sep 4, 2016) Why not answer is 0.6990?

 Muhammad Asif said: (Oct 10, 2016) Please explain me, I didn't understand.

 Ravi said: (Dec 3, 2016) B is right. I agree with that.

 I.Kiran Kumar said: (Dec 17, 2016) Please explain it, I didn't understand.

 Lavanyageetha said: (May 19, 2017) What is the answer for this question? Log 64 base 16- log 16 base 64?

 Chand said: (Jul 3, 2018) How 10000 came? Please explain it.

 Sanjay said: (Jul 7, 2018) 0.3010 is in decimals, to remove decimals we add zeros.

 Mahalakshmi said: (Sep 5, 2018) How these base can be changed over here please explain?

 Shiv said: (Oct 6, 2018) Simply log2^10 is reciprocal of log 10^2 so, log2^10=1/log10^2. =1/0.3010=10000/3010(removing decimal), =1000/301.

 Sagor said: (Jan 1, 2019) We know, loga M= logb M ÷ logb a, so, log2 10= log10 10 ÷ log10 2 [here b= 10], =1 ÷ 0.3010, =10000 ÷ 3010, =1000/301.

 Sydha said: (Jan 17, 2019) I am not getting the answer, please explain it.

 Pandichitra said: (Mar 28, 2019) Thanks @Sagor.

 Navya said: (May 7, 2019) I can't understand this problem. Please explain in detail.

 Karma said: (Sep 21, 2019) @Chand. To remove a decimal, we multiply both the numerator and denominator by 10000.