THX
更新1:
仲有一題, If the height of a triangle is decreased by 25% while its base is increased by 30%, find the percentage change in its area.
F3 percentage
2007-11-12 2:57 am
If a number is first increased by 40% and then decreased by a%, the overall percentage change of the number is +12%. Find a.
THX
THX
回答 (2)
2007-11-12 3:06 am
✔ 最佳答案
Let x be the numberx [(1+40%) (1 - a%)] = x (1+12%)
(1+40%) (1 - a%) = 1+12%
1 + 40% - a% (1.4) = 1 + 12%
a% = 28% / 1.4 = 20%
a=20
2007-11-15 15:35:17 補充：
仲有一題, the percentage change in its area.= (1 - 25%) (1 + 30%) - 1= (0.75) (1.3) - 1= 0.975 - 1= -0.025= -2.5%The area is decreased by 2.5%
2007-11-12 3:07 am
Let the number be X
X * (1+40%)*(1+a%) = X*(1+12%)
1.4 * (1+a%) = 1.12
(1+a%) = 0.8
a% = 0.8 - 1
a% = -.2
a = -20%------------------------Answer
X * (1+40%)*(1+a%) = X*(1+12%)
1.4 * (1+a%) = 1.12
(1+a%) = 0.8
a% = 0.8 - 1
a% = -.2
a = -20%------------------------Answer
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原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071111000051KK03901