Răspuns :
x:z - y:z = 5 => z(x-y)=5
si x-y=20
⇵
z * 20 = 5
adica: z = 5/20 = 1/4 = 0,25
Proba: 1/4 * 20 = 20:4 = 5 (adevarat)
si x-y=20
⇵
z * 20 = 5
adica: z = 5/20 = 1/4 = 0,25
Proba: 1/4 * 20 = 20:4 = 5 (adevarat)