UC知道英语数学题超级高分！（急）回答好的加200分、！！！！
来源：百度知道 编辑：UC知道 时间：2024/06/07 06:24:51
(b) The Red Cross wishes to determine the composition of 1000 identical food parcels, each of which
is to be packed into a 20 litre container. For each possible food, its density, dietary value per
kilogramme and availability are given in the table below.
Item 1 2 3
Density (kg/litre) 0.1 0.2 0.25
Dietary value (units/kg) 10 6 3
Availability (kg) 2000 3000 10000
(i) Model the problem of maximizing the total dietary value of the food parcels as a linear
programming problem. [You should assume that the foods can be packed without any air
spaces!]
(ii) Solve the problem formulated in (i) both graphically (after using the equation to eliminate
one of the variables) and by assigning variables according to their knapsack value
is to be packed into a 20 litre container. For each possible food, its density, dietary value per
kilogramme and availability are given in the table below.
Item 1 2 3
Density (kg/litre) 0.1 0.2 0.25
Dietary value (units/kg) 10 6 3
Availability (kg) 2000 3000 10000
(i) Model the problem of maximizing the total dietary value of the food parcels as a linear
programming problem. [You should assume that the foods can be packed without any air
spaces!]
(ii) Solve the problem formulated in (i) both graphically (after using the equation to eliminate
one of the variables) and by assigning variables according to their knapsack value
红十字会希望确定组成的1000相同的食品包裹，每个要装入20升的容器。对于每个可能出现的粮食，其密度，膳食价值每公斤和可用性得到见下表。
项目 1 2 3
密度（千克/升） 0.1 0.2 0.25
膳食价值（单位/千克） 10 6 3
供货情况（公斤） 2000 3000 10000
1模型的问题，最大限度地提高膳食的总价值的食品包裹的线性
规划问题。 [您应承担的食品可以在没有任何空气便携
空间！ ]
2解决这个问题制订的（一）既生动（后使用方程消除
一个变量）和变量赋值根据自己的背包价值
(i) . X,Y,Z分别为每包食品中三种食品的体积
X+Y+Z=20
因为每种食品的供应量分别是2000, 3000, 10000,而且是完全相同的1000包,所以:
0.1X<2000/1000
0.2Y<3000/1000
0.25Z<10000/1000
即
X<20
Y<15
Z<40
求什么情况下,10(0.1X)+6(0.2Y)+3(0.25Z)=X+1.2Y+0.75Z的值最大.
(ii) .
因为X+Y+Z=20
所以X=20-y-Z
代入X+1.2Y+0.75Z得
20+0.2Y-0.25Z
要20+0.2Y-0.25Z的值最大,Z必须为零.
公式变成
X+Y=20
求20+0.2Y最大值
因为Y<15
所以
X=5 Y=15 Z=0 时, X+1.2Y+0.75Z的值最大(23).
图表法只能你自己画了,这里画不了.