300X：500y：600Z=1:1:1
3X：5y：6Z=1:1:1
3x:5y=1:1
x=5y/3
5y：6Z=1:1
z=5y/6
x+y+z=63
5y/3+y+5y/6=63
10y/6+y+5y/6=63
21y/6=63
y/6=3
y=18
x=5y/3=18*5/3=30
z=5y/6=18*5/6=15
所以x=30,y=18,z=15