Question

If $\frac{1}{5}:\frac{1}{x}=\frac{1}{x}:\frac{1}{125}$, then the value of $x$ is ________.

• A. $1.25$
• B. $1.5$
• C. $25$
• D. $2.25$

Answer 1

The correct option is C $25$

Given that $\frac{1}{5}:\frac{1}{x}=\frac{1}{x}:\frac{1}{125}$

Thus we have $\frac{1/5}{1/x}=\frac{1/x}{1/125}$

$\Rightarrow \frac{x}{5}=\frac{125}{x}$

$\Rightarrow x^2=5\times 125$

$\Rightarrow x=$ $\sqrt{5\times 125}=25$