Notam:
x=numarul de muncitori
e=numarul de electricieni
m=numarul de mecanici
e=2/7 × x
m=3/5 × 5/7 × x = 3/7 × x
instalatori=12
2/7 × x + 3/7 × x + 12 = x
5/7 × x + 12 = x |×7
5x + 84 = 7x ⇒ 84 = 2x
x=42
e=2/7 × 42=
=2 × 6
e=12
m=x - e - i =
=42-12-12
m=24
