Re: [計量] If 55 percent of people have brown ...
※ 引述《Ph7 (褪去色彩脫胎重生)》之銘言:
: 1. If 55 percent of a group of peopole have brown hair and 80 percent
: of the same group do not have red hair, what fraction of those who
: do not have brown hair have red hair???
: A.1/4
: B.4/11
: C.4/9
: D.5/9
: E.4/5
: 題意不是很請清楚
: 請大大幫個忙解釋一下
: ANS: C
55% brown hair → 45% not brown hair
80% not red hair → 20% red hair
則非棕髮的人(45%)當中,多少比例的人有紅色頭髮(20%):
20/45 = 4/9 → C
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◆ From: 140.109.29.198
※ 編輯: echovan 來自: 140.109.29.198 (11/30 14:48)
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