x:y=3:2 ,y=2x/3(1)
y:z=5:4 ,z=4y/5(2)
x+y+z=66 (3)
把(1)代入(2)得:z=8x/15
x+2x/3+8x/15=66
x=30,将其代入(1)得:y=20,再将它(2)得:z=16