1)X-? Y-? Z-? 123=x+y+z x:y=2:5 y:z=3:4 2) X-? Y-? Z-? 145=x+y+z x:y=4:3 y:z=2:5
X=2y/5 z=4y/3 123=2y/5+y+4y/3 123=(6y+15y+20y)/15 123*15=41y y=123*15/41 y=45 x=2*45/5 x=18 z=4*45/3 z=60 x=4y/3 z=5y/2 145=4y/3+y+5y/2 145=(8y+6y+15y)/6 145*6=29y y=145*6/29 y=30 x=4*30/3 x=40 z=5*30/2 z=75