$100在增加了25%後再減少30%,求新值.
某數y減少35%後再增加30%,求百份數増減.
以科學記數法表示答案及準確至２位有效數字.
(a) (2x10^102)+(3x10^103)
(b) (4x10^4)^2
有冇人識計黎幾題牙......教下我
2006-10-29 10:32 pm
回答 (4)
2006-10-29 10:44 pm
✔ 最佳答案
1: 100*(1+25%)*(1-30%)=100*1.25*0.7
=87.5
2:
(1-35%)*(1+30%)
=0.65*1.3
=0.845
so百份數増減
=0.845-1
= -0.155
= -15.5%
3a:
(2*10^102)+(3*10^103)
=(0.2*10^103)+(3*10^103)
=(3+0.2)*10^103
=3.2*10^103
3b:
(4*10^4)*2
=4^2*(10^4)^2
=8*10^8
2006-10-29 14:56:38 補充：
3b:(4*10^4)*2=4^2*(10^4)^2=16*10^8=1.6*10^9呢個先岩＝＝
參考: me
2006-10-29 10:44 pm
100 x (1+25%) x 30%
= 100 x 125% x 30%
=125 x 30%
= 37.5
= 100 x 125% x 30%
=125 x 30%
= 37.5
2006-10-29 10:44 pm
100X(1+25%)X(1-30%)=87.5
設Y係一個實數...um,,當佢係,,50
50X(1-35%)X(1+30%)
= 50X65%X130%
= +42.25
其他用計算機LA
設Y係一個實數...um,,當佢係,,50
50X(1-35%)X(1+30%)
= 50X65%X130%
= +42.25
其他用計算機LA
參考: ME
2006-10-29 10:41 pm
1. = 100x(1+25%)x(1-30%)
= 87.5
2. = [yx(1-35%)x(1+30%) -y] / y x100%
= (0.845y-1)x100%
= -15.5%
2006-10-29 14:44:06 補充：
b) =1600000000 = 16x10^8
2006-10-29 14:46:01 補充：
a) (2x10^102) (3x10^103) =(0.2x10^103) (3x10^103) =(3 0.2)x10^103 =3.2x10^103
= 87.5
2. = [yx(1-35%)x(1+30%) -y] / y x100%
= (0.845y-1)x100%
= -15.5%
2006-10-29 14:44:06 補充：
b) =1600000000 = 16x10^8
2006-10-29 14:46:01 補充：
a) (2x10^102) (3x10^103) =(0.2x10^103) (3x10^103) =(3 0.2)x10^103 =3.2x10^103
收錄日期: 2021-04-12 23:51:36
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20061029000051KK02597