數學問題 !!!!!!!要步驟!!!!!!!!!!!!!!!

2014-01-19 1:46 am

1. The profit percentage of a watch is 30%.If the watch is now sold at a discount of 20%,find the new profit percentage
2.in triangle ABC , AB=7cm,BC=9cm and AC=ycm,where y is an positive integer.Find the greastest possible value of y.
3.In the first term,the ratio of the numbers of boys to girls in F3 is 3:2.If the number of girls is decreased by 18% and that of the boys is increased by 14% in the second term,what is the percentage change in the number of students in F.3?

更新1:

要步驟!!!!!!!!!!!!!!!

回答 (3)

用戶4366

2014-01-19 2:18 am

✔ 最佳答案

1. 售價P = (1.3)C [ C是成本 ]

新售價P' = P(0.8P) = (0.8)(1.3C) = 1.04C

新利潤為 4%

2. 三角形任何一邊長度必少於其餘兩邊之和。

9+7 = 16
y = 15
如果 y = 16，哪是一直線而非三角形了。

2014-01-18 18:28:37 補充：
設原本學生總數為 x ，

上學期 :
男生人數 B = (3/5)x = 0.6x
女生人數 G = (2/5)x = 0.4x

下學期 :
男生人數 B' = (1.14)B = (1.14)(0.6x) = 0.684x
女生人數 G' = (1-0.18)(0.4x) = 0.328x

總人數 x' = B' + G' = 0.684x + 0.328x = 1.012x

所以，總人數上升了 1.2%

2014-01-18 18:31:09 補充：
更正 :

新售價P' = P(0.8P) = (0.8)(1.3C) = 1.04C

應該為 :

新售價P' = (0.8P) = (0.8)(1.3C) = 1.04C

P(0.8P) 最前面的 P 是打多了的。

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[匿名]

2014-01-20 9:06 pm

這里很不錯ａａａｓｈｏｐｓ。ｃｏｍ老婆很喜歡
哥份倱啈

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[匿名]

2014-01-20 11:38 am

快去這里*****我每次都是去這里看
伨勅

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