Logarithms | Arithmetic aptitude | Discussion Page

1)

$\frac{1}{\log_{xy}{xyz}}+\frac{1}{\log_{yz}{xyz}}+\frac{1}{\log_{zx}{xyz}}$ is

A) 1

B) 2

C) log 2

D)

$\frac{1}{2}$

Option B

$\frac{1}{\log_{xy}{xyz}}+\frac{1}{\log_{yz}{xyz}}+\frac{1}{\log_{zx}{xyz}}$

= $\log_{xyz}{xy}+\log_{xyz}{yz}+\log_{xyz}{zx}$

= $\log_{xyz}{xy\times yz\times zx}$

= $\log_{xyz}{(xyz)^{2}}$

= $2\log_{xyz}{xyz}$

=2\times 1

=2

Discussion Forum