1.The marked price of a dress is 300$.By what percentage should the marked price be increased so that the selling price is 300$ after giving a discount of 20%?
2.A sum of money is evenly distributed to 15 people.If the amount remains unchanged,but the number of people is increased by 20%,find the percentage decrease of the amount each one receives.
本書後面第1條同第2條既答案分別係25%同埋16又3分之2%
數學問題，幫幫手念下點計，急
2007-10-14 3:17 am
回答 (2)
2007-10-14 3:26 am
✔ 最佳答案
1. 300x(1+x%) = 300除(1-20%)= 1.25
the marked price be increased 25%.
2.[15除(1+20%)] 除15
= 83.333...%
decrease = 1-83.3333%
=16.66666...%
= 16又3分之2%
2007-10-13 19:27:24 補充：
打錯野,第一條x= 25唔係1.25
2007-10-14 4:15 am
第1題:設X=上升百分比
300*[(100+X)/100]*[(100-20)/100]=300
(300+3X)*(80/100)=300
2400+8X=3000
X=25
所以ANS=25%
第2題:唔識~~SORRY!! >.<"
300*[(100+X)/100]*[(100-20)/100]=300
(300+3X)*(80/100)=300
2400+8X=3000
X=25
所以ANS=25%
第2題:唔識~~SORRY!! >.<"
收錄日期: 2021-04-26 15:51:02
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071013000051KK04131