甲、乙、丙、丁各做xyzt
x+y+z+t=270
甲x+10,乙y-10丙2z丁t/2
x+10=2z x=2z-10
y-10=2z y=2z+10
t/2=2z t=4z
2z-10+2z+10+z+4z=270
z=30
x=2*30-10=50
y=2z+10=30*2+10=70
t=4z=30*4=120
甲、乙、丙、丁各做xyzt
x+y+z+t=270
甲x+10,乙y-10丙2z丁t/2
x+10=2z x=2z-10
y-10=2z y=2z+10
t/2=2z t=4z
2z-10+2z+10+z+4z=270
z=30
x=2*30-10=50
y=2z+10=30*2+10=70
t=4z=30*4=120