A farmer has 2 brands of fertilizers.Brand A Contains 15%
acid,Brand B contains 7% acid.If the farmer wants to prepare 80 kg
of
fertilizer containing 10% acid .How much Brand A &Brand B
fertilizers should be mixed?
THANK YOU
Maths F.3聯立二元一次方程 (Quick!!!)
2008-03-21 7:04 am
回答 (3)
2008-03-21 7:28 am
✔ 最佳答案
Let Brand A be x,Brand B be y.x*15%+y*7%=80*10%
0.15x+0.07y=80*10%
15x+7y=800.....(1)
x+y=80.....(2)
(2)*15: 15x+15y=1200
(2)-(1) 8y=400
y=50
Put y=50 into (1)
15x+7(50)=800
15x=450
x=30
So Brand A should contain 30kg, Brand B should contain 50kg
參考: Myself!
2008-03-21 4:03 pm
Let Brand A be x,Brand B be y.
x*15%+y*7%=80*10%
0.15x+0.07y=80*10%
15x+7y=800.....(1)
x+y=80.....(2)
(2)*15: 15x+15y=1200
(2)-(1) 8y=400
y=50
Put y=50 into (1)
15x+7(50)=800
15x=450
x=30
So Brand A should contain 30kg, Brand B should contain 50kg
2008-03-21 08:03:42 補充：
Let Brand A be x,Brand B be y.
x*15%+y*7%=80*10%
0.15x+0.07y=80*10%
15x+7y=800.....(1)
x+y=80.....(2)
(2)*15: 15x+15y=1200
(2)-(1) 8y=400
y=50
Put y=50 into (1)
15x+7(50)=800
15x=450
x=30
So Brand A should contain 30kg, Brand B should contain 50kg
x*15%+y*7%=80*10%
0.15x+0.07y=80*10%
15x+7y=800.....(1)
x+y=80.....(2)
(2)*15: 15x+15y=1200
(2)-(1) 8y=400
y=50
Put y=50 into (1)
15x+7(50)=800
15x=450
x=30
So Brand A should contain 30kg, Brand B should contain 50kg
2008-03-21 08:03:42 補充：
Let Brand A be x,Brand B be y.
x*15%+y*7%=80*10%
0.15x+0.07y=80*10%
15x+7y=800.....(1)
x+y=80.....(2)
(2)*15: 15x+15y=1200
(2)-(1) 8y=400
y=50
Put y=50 into (1)
15x+7(50)=800
15x=450
x=30
So Brand A should contain 30kg, Brand B should contain 50kg
2008-03-21 3:48 pm
Let Brand A be x,Brand B be y.
x*15%+y*7%=80*10%
0.15x+0.07y=80*10%
15x+7y=800.....(1)
x+y=80.....(2)
(2)*15: 15x+15y=1200
(2)-(1) 8y=400
y=50
Put y=50 into (1)
15x+7(50)=800
15x=450
x=30
So Brand A should contain 30kg, Brand B should contain 50kg
x*15%+y*7%=80*10%
0.15x+0.07y=80*10%
15x+7y=800.....(1)
x+y=80.....(2)
(2)*15: 15x+15y=1200
(2)-(1) 8y=400
y=50
Put y=50 into (1)
15x+7(50)=800
15x=450
x=30
So Brand A should contain 30kg, Brand B should contain 50kg
收錄日期: 2021-04-16 14:02:46
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