\(0.27+\dfrac{1}{2}< \dfrac{x}{100}< 1-\dfrac{20}{100}\)
\(\Leftrightarrow\dfrac{27}{100}+\dfrac{50}{100}< \dfrac{x}{100}< \dfrac{80}{100}\)
\(\Leftrightarrow\dfrac{77}{100}< \dfrac{x}{100}< \dfrac{80}{100}\)
\(\Leftrightarrow77< x< 80\)
vậy \(x=\left\{78;79\right\}\)