X+Y+Z=3.3 X/3+Y/4+X/5=51/60(这里是不是Z/5?) Z/3+Y/4+X/5=53.4/60
可以得到X+Y+Z=3.3①,20X+15Y+12Z=51②,20Z+15Y+12X=53.4③
③-②化简得Z-X=0.3,代入①中得2X+Y=3,代入③中得32X+15Y=47.4
2X+Y=3,30X+15Y=45,32X+15Y=47.4
得到X=1.2,∴Z=1.5,Y=0.6
X=1.2,Y=0.6,Z=1.5
若有疑问可以百度Hi聊、