a+b+c+d=1500
a=1/2b b=2a
a=1/3c c=3a
(a+b+c)-(b+c+d)=40
a+b+c-b-c-d=40
a-d=40
a=d+40
si inlocuim in a+b+c+d=1500
(d+40)+2(d+40)+3(d+40)+d=1500
d+40+2d+80+3d+120+d=1500
7d+240=1500
7d=1260
d=180
a=d+40=180+40=220
b=2a=2x220=440
c=3a=3x220=660
a+b+c+d=220+440+660+180=1500