In a clearance sale , Susan bought a T-shirt marked at $120 at a discount of 40%,a pair of jeans marked at $180 at a discount of 20% , and a jacket marked at $300 at a certain discount .Because Susan paid the bill by credit card ,she could have an extra discount of 10% and the amount she paid was $437.4.
a) If Susan paid the bill by cash ,how much wwould she pay?
b) Find the discount percent of the jacket.
點解&點做,有多種計法請比我,列所有步驟!10分
math question F.1 10分
2007-12-08 3:08 am
回答 (2)
2007-12-08 3:51 am
✔ 最佳答案
a)437.4(1-10%)=$486
so she would pay $486 if she pay the bill by cash.
b)let the discount percent of the jacket be x.
[120(1-40%)+180(1-20%)+300(1-x%)](1-10%)=437.4
120(1-40%)+180(1-20%)+300(1-x%)=486
216+300(1-x%)=486
300(1-x%)=270
1-x%=270/300
1-x%=0.9
-x%=-0.1
x=10%
so the discount of the jacket is 10%
2007-12-07 19:52:16 補充：
it should be 300x......so the discount is 1-10%=90%
參考: myself
2007-12-08 3:19 am
a)Let x be the amount of money Susan need to pay if she uses cash,
(1-10%)x=$437.4
x=$437.4/90%
x=$486
b)Let y be the discount of the jacket,
120*(1-40%)+180*(1-20%)+300y=486
72+144+300y=486
300y=486-72-144
300y=270
y=270/300
y=90%
(1-10%)x=$437.4
x=$437.4/90%
x=$486
b)Let y be the discount of the jacket,
120*(1-40%)+180*(1-20%)+300y=486
72+144+300y=486
300y=486-72-144
300y=270
y=270/300
y=90%
參考: Me
收錄日期: 2021-04-23 20:42:00
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