x+y+z=3000
x-75/100*x=y-80/100*y=z-2/3*z
x-3x/4=y-4y/5=z-2z/3 aducem la acelasi numitor(60)
60x-45x=60y-48y=60z-40z
15x=12y=20z
15x=12y
x=12y/15
20z=12y
z=12y/20 si inlocuim in suma
12y/15+y+12y/20=3000 aducem la acelasi numitor (60)
48y+60y+36y=180000
144y=180000
y=1250
x=12*1250/15=1000
z=12*1250/20=15000/20=750