Question

If $\frac{1}{5}:\frac{1}{x}::\frac{1}{x}:\frac{1}{1.25}$, then $x=$?

• A. $1.5$
• B. $2$
• C. $2.5$
• D. $3.5$

Answer 1

The correct option is C $2.5$

Given, $\frac{1}{5}:\frac{1}{x}::\frac{1}{x}:\frac{1}{1.25}$

The four numbers are in proportion

$\therefore \frac{1}{x}\times \frac{1}{x}=\frac{1}{5}\times \frac{1}{1.25}$

$\frac{1}{x^2}=\frac{1}{6.25}$

$x^2=6.25$
$\therefore x=2.5$