Question

If $\frac{1}{5}:\frac{1}{x}=\frac{1}{x}:\frac{1}{1.25}$, then the value of x is

• A. 5
• B. 2.5
• C. 5.2
• D. 2

Answer 1

The correct option is B

2.5

$\frac{1}{5}:\frac{1}{x}=\frac{1}{x}:\frac{1}{1.25}$

$\to$ $\frac{1}{x}$$\times \frac{1}{x}=\frac{1}{5}\times \frac{1}{1.25}=\frac{4}{25}$

$\to \left(\frac{1}{x^2}\right)=\frac{4}{25}$

$\to x^2=\frac{25}{4}$

$\to x=\frac{5}{2}=2.5$