Mr.Chan had some money.He spent 30% on the first day.Then he spent 25% of the remaining amount on the second day and he got $1680 left.
a)How much did he have originally?
b)If Mr.Chan spent another $320,what percentage of the money did he spent altogether?
詳細solution...因為真系唸左好耐5識,所以solution中+英優先考慮,only英文就...睇下點=]only中文就無得傾
數學題Basic Concepts of Percentages
2006-12-31 7:39 pm
回答 (4)
2006-12-31 7:54 pm
✔ 最佳答案
a) Let $X be the amount who Mr. Chan had originallyX(1-30%)(1-25%)=1680
X(70%)(75%)=1680
X(70%)(75%)x100/70x100/75=1680x100/70x100/75
X=3200
b)The percentage of the money
=(3200-1680)+320
______________________X100%
3200
=57.5%
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2006-12-31 7:55 pm
a) Let the original money be y
(y x (1-30%)) x (1-25%) = 1680
0.7y x 0.75 = 1680
0.7y = 2240
y = 3200
The Original money that Mr Chan have is $3200.
b) The First Day spent
3200 x 30% = 960
The Second Day spent
(3200 -960) x 25% = 560
The percentage of the money that Mr Chan spent altogether is:
((960+560+320)/3200) x 100%
=57.5%
(y x (1-30%)) x (1-25%) = 1680
0.7y x 0.75 = 1680
0.7y = 2240
y = 3200
The Original money that Mr Chan have is $3200.
b) The First Day spent
3200 x 30% = 960
The Second Day spent
(3200 -960) x 25% = 560
The percentage of the money that Mr Chan spent altogether is:
((960+560+320)/3200) x 100%
=57.5%
2006-12-31 7:52 pm
let x be the originally.
a) x * (1-30%) *(1-25% )= 1680因為佢果25%係用完30%先去計, 所以先用一減去%, 另外問題問你佢再用埋25%之後才餘下1680, 所以都要用1去減%
x =3200
b) 3200*30%+(3200*70%*25%)+320 /3200 *100%將所有用左既錢加埋再over原有既錢就得啦
=57.5%
a) x * (1-30%) *(1-25% )= 1680因為佢果25%係用完30%先去計, 所以先用一減去%, 另外問題問你佢再用埋25%之後才餘下1680, 所以都要用1去減%
x =3200
b) 3200*30%+(3200*70%*25%)+320 /3200 *100%將所有用左既錢加埋再over原有既錢就得啦
=57.5%
2006-12-31 7:51 pm
a)
Let he had $A originally
A(1-30%)(1-25%)=1680
0.525A=1680
A=3200
b)
the % of the money he spent altogether?
[3200(1-30%)(1-25%)-320]/3200*100%
=(1680-320)/3200*100%
=1360/3200*100%
=0.425*100%
你條問題錯grammar-.-
what percentage of the money did he spent altogether?
=42.5%
Let he had $A originally
A(1-30%)(1-25%)=1680
0.525A=1680
A=3200
b)
the % of the money he spent altogether?
[3200(1-30%)(1-25%)-320]/3200*100%
=(1680-320)/3200*100%
=1360/3200*100%
=0.425*100%
你條問題錯grammar-.-
what percentage of the money did he spent altogether?
=42.5%
參考: me
收錄日期: 2021-04-12 21:00:47
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