[問題] Please help a "vegetable bird" like me

看板GMAT (GMAT入學考試)作者 (Heart fly)時間16年前 (2008/09/12 12:27), 編輯推噓3(301)
留言4則, 3人參與, 最新討論串1/5 (看更多)
1.How many different 6-letter sequences are there that consist of 1 A, 2 B's, and 3 C's? A:60 2.Apharmaceutical company received $3million in royalties on the firs $20 million in sales of the generic equivalent of one of its products and then $9million in royalties on the next $108 million in saes. By approximately what percent did the ratio of royalties to sales decrease from the first $20 million in sales to the next $108 million in sales? A:45% ps. The first question is I have a gap in memory of permutation formula The second question is I am a little bit confused with its meaning. Is the following equation right? [3/20-9/108]/ 9/108=87.5% Thanks for your patience. -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 218.166.209.137

09/12 14:42, , 1F
1. 6(C5取2)(C3取3) 2.[3/20-9/108]/(3/20)=0.446
09/12 14:42, 1F

09/12 14:56, , 2F
能不能請flac大解釋一下1的算法啊 @@?
09/12 14:56, 2F

09/12 15:21, , 3F
補充一下 用rookie會比vegetable bird好 哈
09/12 15:21, 3F

09/13 01:32, , 4F
謝謝flac。
09/13 01:32, 4F
文章代碼(AID): #18oU-gtx (GMAT)
文章代碼(AID): #18oU-gtx (GMAT)