form 1 maths

(a) If Ronald saves $18 at a discount of 25%. find the selling price of the product in shop A

Selling price
=discount/discount rate
=$18/25%
=$72


(B) If Edmond only saves $13.5 when he buys the product in shop B , find the perecntage discount offered by shop B

Ronald buys the product in shop A at price
= $72-18
=$54

As Ronald and Edmond buy the same product at the same price in shop A and shop B respesctively,

Edmond buys the product in shop B at price=$54

Discount offered by shop B
=(discount/total price)x100%
=[13.5/(54+13.5)]x100%
=20%



2010-12-04 15:00:42 補充：
"buy the same product at the same price"
係實際俾果個價錢一樣,唔係未折個selling price一樣!!!!

1 a) The selling price of the product in Shop A is

$18 / 25 %
= $18 x 100/ 25
= $ 72.0


1 b) The percentage discount offered by shop B

13.5 / 72 x 100%

= 18.75 %

(a) Let A be price of shop A
A x 25% = 18
A = 72

(b) As price of shop A = shop B
Let Y% be the discount rate
A x Y = 13.5
Y = 13.5 / A
Y = 13.5/72
= 18.75%