Question:
The sum of a number and its reciprocal is $2 \frac{1}{30}$. Find the number.
Solution:
Let the required number beĀ x.
According to the given condition,
$x+\frac{1}{x}=2 \frac{1}{30}$
$\Rightarrow \frac{x^{2}+1}{x}=\frac{61}{30}$
$\Rightarrow 30 x^{2}+30=61 x$
$\Rightarrow 30 x^{2}-61 x+30=0$
$\Rightarrow 30 x^{2}-36 x-25 x+30=0$
$\Rightarrow 6 x(5 x-6)-5(5 x-6)=0$
$\Rightarrow(5 x-6)(6 x-5)=0$
$\Rightarrow 5 x-6=0$ or $6 x-5=0$
$\Rightarrow x=\frac{6}{5}$ or $x=\frac{5}{6}$
Hence, the required number is $\frac{5}{6}$ or $\frac{6}{5}$.