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