设甲、乙、丙三种蔬菜用了X Y Z 车
(1)x+y+z=20
(2)2*5x+1*7y+1.5*4z=183 10X+7Y+6Z=183
(3)2x+y+1.5z=36
(1)*1.5-(3) 1.5X+1.5Y+1.5Z-2X-Y-1.5Z=20*1.5-36
0.5Y-0.5X=-6
X-Y=12
X=12+Y
(1)*10 -(2) 10X+10Y+10Z-10X-7Y-6Z=20*10-183
3Y+4Z=17 ----Z=(17-3Y)/4
=4.25-0.75Y
X+Y+Z=20
12+y+Y+4.25-0.75Y=20
16.25+1.25Y=20
Y=3
Y=3
X=12+3=15
Z=4.25-0.75*3=2
甲种蔬菜15车 乙种蔬菜3车 丙种蔬菜2车