Răspuns:
70 minute; 8,75 minute
Explicație pas cu pas:
[tex] \frac{3}{x} + \frac{2}{y} = \frac{1}{5} \\ \frac{1}{x} + \frac{1}{y} = \frac{1}{14} < = > \frac{3}{x} + \frac{3}{y} = \frac{3}{14} \\ (\frac{3}{14} - \frac{3}{y}) + \frac{2}{y} = \frac{1}{5} \\ \frac{1}{y} = \frac{1}{70} = > y = 70 \\ x = 17.5 \\ \\ \frac{1}{m} = \frac{2}{x} = > m = \frac{ x}{2} \ = \frac{17.5}{2} = 8.75[/tex]