哪位好心人能帮忙算一下这道PS？求解题过程，万分感谢

norlanzhang · 发表于 2012-2-28 18:09:43

Seed mixture X is 40 percent ryegrass and 60 percent bluegrass by weight; seed mixture Y is 25 percent ryegrass and 75 percent fescue. If a mixture of X and Y contains 30 percent ryegrass, what percent of the weight of this mixture is X?

狒狒919 · 发表于 2012-2-28 18:24:48

不确定哎，答案是33.3%，三分之一吗？

norlanzhang · 发表于 2012-2-28 18:30:05

嗯。怎么算的啊？

狒狒919 · 发表于 2012-2-28 18:40:51

嗯。怎么算的啊？

-- by 会员 norlanzhang (2012/2/28 18:30:05)

设X为m percent, 则Y为1-m percent， x=40%r+60%b, y=25%r+75%f, mixture 的r%=40%*m+25%*(1-m)=30%可以算出m=33.3%

treewing929 · 发表于 2012-2-28 18:42:30

哦! 明白了! !!

norlanzhang · 发表于 2012-2-28 18:49:45

嗯，多谢了~

哪位好心人能帮忙算一下这道PS？求解题过程，万分感谢

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