Răspuns :
[tex]5\ \ muncitori\ \ ............\ \ 18\ \ zile\ \ .............\ \ 8\ \ ore \\ \\ 9\ \ muncitori\ \ ............\ \ x\ \ zile\ \ ...............\ \ 10\ \ ore \\ \\ x= \frac{5*18*8}{9*10} =>x= \frac{720}{90} =>x=8\ \ zile[/tex]
5m.....18zile.....8h
9m.....x zile......10 h
18 zile*8h/zi= 144 h
5m.......144 h
9m.....z zile
5*144=9*z
Zz 80h
x= 80h: 10
x=8 zile