How To Solve Logarithm Questions Quickly

How To Solve Logarithm Question Quickly:-

• One of the most important and marks scoring section in Aptitude is Logarithm. Logarithm might be confusing but once you start solving it; it will become one of the easiest topics you have ever solved.
• This page will help you out in solving the problems regarding Logarithm.
• Before solving the Logarithm problem the first thing you have to do is take an idea about What is logarithm?
• A logarithm is a power to which a number must be raised to get another number.
• There are some basic formulas which are required to Solve Logarithm Questions quickly.

Logarithm Formulas:

1.  log_x X= 1
2. log_a 1= 0
3. log_ax =  \frac{1}{log_x a} \
4. log_a(x ^p) = p(log _ax)
5. log_a x=  \frac{log X}{log a}
6. log_a \frac{x}{y} \ = log_a X- log_a Y
7. log_a (xy)= log_aX+ log_aY

Question 1  If log 27= 1.431, then the value of log 9 is?

Option:

A) 0.945

B) 0.934

C) 0.958

D) 0.954

Solution:     log 27= 1.431

\implies log(3)³= 1.431

\implies 3log 3= 1.431

\implies log3= 0.477

therefore, log9= log 3²= 2 log3= (2×0.477)= 0.954

Correct Answer: D

Question 2 If log \frac{a}{b} \ +log \frac{b}{a} \ = log(a+b), then

Option:

A) a-b=1

B) a=b

C) a+b=1

D)a²-b² = 1

Solution:    log \frac{a}{b} \ + log \frac{b}{a} \ = log(a+b)

\implies log (a+b)= log ( \frac{a}{b} \ x \frac{b}{a}) \ = log 1

so, a+b=1

Correct Answer: C