小六數學題..唔知點寫個step 出黎

2007-03-27 12:32 am

一件貨品，若果以原價九折八扣出售，比起原價減價20%後還要少5元，求這件貨品的原價。

已知answer 是62.5元

更新1:

我所列的式是.... A x 90% x 80% = A x (1-20%) -5 有答案當然唔會錯..但係無答案的話就完全唔知點列條式出黎

更新2:

回應 kelvin11051992 : 這條題目的答案是62.5元即 62.5 X 90% X 80% = 62.5 X (1-20%) -5 請清楚問題我問題是..當答案是未知數時...如何出方程以計算並得到最後答案 62.5 呢!!???

回答 (4)

2007-04-03 2:14 am

well done

👍 0 👎 0

2007-03-27 2:58 am

Let x be the money of this product.

80%(90%x) =(1-20%)x -5
72%x = 80%-5
5=8%x
x=62.5

Therefore the money of the product is $62.5.

👍 0 👎 0

2007-03-27 12:38 am

設這件貨品的原價為y元
y*80%-5=62.5
y*(80/100)-5+5=62.5+5
y*(80/100*100)=67.5*100
y*80/80=6750/80
y=84.375

參考: me

👍 0 👎 0

2007-03-27 12:37 am

設這件貨品的原價為y元!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

👍 0 👎 0