Learning from Mistakes
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Peter claims that when a number x is increased by 10% and then decreased by 10% , the value of x is unchanged.
His calculation：x ( 1 + 10% - 10% )=x
Peter is wrong.Point out the mistake
有1題數學題5識呀.....help help 我 thz~! (10點)
2007-07-28 2:52 am
回答 (3)
2007-07-28 3:02 am
✔ 最佳答案
It must be:x(1+10%)(1-10%)but x ( 1 + 10% - 10% ) means that once you have x ,then you have x's 10% more and then lose x's 10%
2007-07-28 2:20 pm
=x(1+10%)(1-10%)
2007-07-28 3:08 am
a * 1.1 = 1.1a
1.1a x (1-0.1) = 1.1a x 0.9 = 0.99a
1.1a x (1-0.1) = 1.1a x 0.9 = 0.99a
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原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070727000051KK04376