線性規劃的問題 - 經濟

※ 引述《mei555 (mei)》之銘言：
: 題目:1. George needs to find at least 12 lb of gold and at least 18 lb of
: silver to pay the monthly rent. There are 2 mines in which George
: can find gold and silver.Each day that George spends in mine 1 ,he
: finds 2 lb of gold and 2 lb of silver. Each day that George spend
: in mine 2 ,he finds 1 lb of gold and 3 lb of silver. Formulate an LP
: to help George meet his requirements while spending as little time as
: possible in the mines. Graphically solve the LP.

min x+y;
st.
2x+y>=12
2x+3y>=18

我有點忘了lingo的語法，不過大概是這樣…
x是花在1號礦的天數，y是花在2號礦的天數。

: 2.You blend silicon and nitrogen to produce 2types of fertilizers.
: Fertilizer 1 must be at least 40% nitrogen and sells for $70/lb
: Fertilizer 2 must be at least 70% silicon and sells for $40/lb.
: You can purchase up to 80 lb of nitrogen at $15/lb and up to 100 lb
: of silicon at $10/lb . Assuming that all fertilizer preduced can be
: sold, formulate an LP to help you maximize profits.

max Fert1*70+Fert2*40-Nitro1*15-Nitro2*15-Silicon1*10-Silicon2*10
st.
Nitro1 >= 0.4*Fert1
Nitro1+Nitro2 < 80
Silicon2 >= 0.7*Fert2
Silicon1+Silicon2 < 100
Nitro1 + Silicon1 = Fert1
Nitro2 + Silicon2 = Fert2
Nitro1 >= 0
Nitro2 >= 0
Silicon 1 >= 0
Silicon 2 >= 0

: 以上的2個問題要如何設限制式?
: 請大家幫幫忙
: 我們會感激在心的
: 謝謝............
: ps.要特別謝謝之前幫我們解答線性問題的人
: 感謝你

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