Aptitude - Logarithm - Discussion

Discussion :: Logarithm - General Questions (Q.No.4)

4. 

If log 27 = 1.431, then the value of log 9 is:

[A]. 0.934
[B]. 0.945
[C]. 0.954
[D]. 0.958

Answer: Option C

Explanation:

log 27 = 1.431

log (33 ) = 1.431

3 log 3 = 1.431

log 3 = 0.477

log 9 = log(32 ) = 2 log 3 = (2 x 0.477) = 0.954.


Arvind said: (Jan 19, 2012)  
How come log3 value .477

Olamikan Adesanmi said: (Apr 11, 2012)  
You divide 1. 431 by 3, making log3 subject of formula you get log 3 = 0.477

Subham Singh Rathore said: (Nov 11, 2012)  
log27=1.431
log3^3=1.431
3log3=1.431
log3=1.431/3
log3=0.477
log9=log3^2 then
2log3
2*0.477 = 0.954

Hanumanth said: (Dec 15, 2012)  
log27=1.431
log3^3=1.431
3log3=1.431
log3=1.431/3
log3=0.477
log(9*3)=1.431
log9+log3=1.431
log9=1.431-0.477
log9=0.954

Jilpy said: (Jun 5, 2014)  
@Arvind.

Here, 3* log3 = 1.431.

Then,
1.431/3 = 0.477.

Mr. Bean said: (Sep 29, 2014)  
log27 = log(3*9) = log3+log9.

So, log9 = log27-log3.
log9 = 1.4310-0.4771.
log9 = 0.9539 ~ 0.954.

Maria said: (Dec 2, 2014)  
Please tell me how we can divide the value with the point I don't know how to divide with a point value like 3.

Pranjit said: (Feb 17, 2015)  
Its given 1.431 i.e the point is at before three number. Hence we can write:

= 1431/1000.

Now its divide by 3.

= 1431/3-1000.

i.e 477/1000 = 0.477.

Because the numbers of zero three hence the point comes in before three number.

Princi said: (Feb 15, 2016)  
These are very easy steps, use your mind.

Jay Vishwakarma said: (Jun 2, 2016)  
How to draw the graphs of log functions?

Can anyone tell me?

Anouska said: (May 29, 2017)  
Thanks for the solution. It helped a lot.

Shubhek K.R said: (Sep 15, 2018)  
How find value of log3 =0.477? Please explain it.

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