更新1:
tom= farmer
F3數學。英文黎。
2009-10-12 3:42 am
tom has two brands of fertilizers. brand a contains 15% oxygen and brand b contains 7 % oxygen. if farmer wants to perpare 80 kg of fertilizer containing 10% oxygen, how much brand a and brand b fertilizers should be mixed?
回答 (1)
2009-10-12 3:50 am
✔ 最佳答案
Let x kg brand a fertilizers should be mixed ,then
(80 - x) kg brand b fertilizers should be mixed.
x * 15% + (80 - x) * 7% = 80 * 10%
0.15x + 5.6 - 0.07x = 8
0.08x = 2.4
x = 30
30 kg brand a and (80-30) = 50 brand b fertilizers should be mixed.
2009-10-11 19:51:55 補充：
The last line should be :
30 kg brand a and (80-30) = 50 kg brand b fertilizers should be mixed.
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https://hk.answers.yahoo.com/question/index?qid=20091011000051KK01818