[tex]\it Vom\ nota\ cu \ x \ num\breve{a}rul\ cerut.[/tex]
[tex]\it\ \ x+15\%\ din\ x =69 \Rightarrow x+\dfrac{\ 15^{(5}}{100}\cdot x=69 \Rightarrow x+\dfrac{3}{20}x=69|_{\cdot20} \Rightarrow \\ \\ \\ \Rightarrow 20x+3x=69\cdot20 \Rightarrow 23x=69\cdot20|_{:23} \Rightarrow x=3\cdot20 \Rightarrow x=60[/tex]
