Răspuns:
Explicație pas cu pas:
1.
[tex]\frac{a}{b}=\frac{2}{3}=>3a=2b => a=\frac{2b}{3}\\\frac{2a+5b}{3b-2a}=\frac{b(\frac{4}{3}+5)}{b(3-\frac{4}{3})} = \frac{\frac{19}{3}}{\frac{5}{3}}= \frac{19}{5}\\[/tex]
2.
[tex]a) \frac{6}{x}=\frac{4}{2}=> 6*2=x*4 => x = \frac{6*2}{4}=> x = 3\\b) \frac{5}{5x}=\frac{15}{18}=>\frac{1}{x}=\frac{15}{18}=> x = \frac{18}{15}[/tex]
3.
[tex]\left \{ {{\frac{a}{3}=\frac{b}{5}} \atop {2a+5b = 93}} \right. \\\left \{ {5a=3b} \atop {2a+5b = 93}} \right. \\\left \{ {a=\frac{3b}{5}} \atop {2a+5b = 93}} \right. => \frac{6b}{5}+5b = 93 => \frac{31b}{5} = 93 = > b = 93 * \frac{5}{31} = 15\\a = \frac{3b}{5} = \frac{3 * 15}{5} = 9[/tex]
4.
[tex]\frac{a}{9} = \frac{5}{b} => ab = 45\\ab - 5 = 45 - 5 = 40[/tex]
5.
[tex]8 * caiet = 16 lei => caiet = \frac{16}{8} = 2 lei\\6 * caiet = 6 * 2lei = 12lei[/tex]
6.
[tex]ore_{totale} = 4 + 6 + 9 = 19 ore\\muncitor_{1} = 1520 lei * \frac{4}{19} = 320 lei\\muncitor_{2} = 1520 lei*\frac{6}{19} = 480 lei\\muncitor_{3} = 1520 * \frac{9}{19} = 720lei[/tex]
