Răspuns:
Explicație pas cu pas:
x/(1/2) = y/(1/4) = z/(1/5) = k
2x = 4y = 5z = k
x = k/2; y = k/4; z = k/5
_____________________
x + y + z = 57
k/2 + k/4 + k/5 = 57 l × 20
10k + 5k + 4k = 57 × 20
19k = 57×20 l : 19
k = 3×20 ⇒ k = 60
_________________
x = k/2 = 60/2 ⇒ x = 30
y = k/4 = 60/4 ⇒ y = 15
z = k/5 = 60/5 ⇒ z = 12
