中一數學.....聽日交

1) (120/80) x 10 = $15
so the profit percent = (20-15) /20 x 100 % = 25 %

2) let X be the original cost,
X x (1+40%) x (1-10%) = 1.26X
so the profit percent = (1.26X-X) /X x100 % = 26 %

1)
先計80pears 每10個1組有幾組
80/10
=8
再每組$20有幾錢收
8x$20
=$160

profit percent =
profit
_________ x 100%
cost price

160-120
_______ x100%
120

= 1
33 _%
3

2)先計selling price
由於而家唔知cost 係幾多,,,所以用c 代表
(1+40%)c x (1-10%)
=140%cx90%
=1.4cx0.9
=1.26c
P.S. 1.4=140%向前移2位,,0.9=90%向前移2位

profit percent =
profit
_________ x 100%
cost price

1.26c-1c
______ x100%
c

0.26 x100%
=26%

P.S. c 上下約左....0.26 向後移2位=%

(1)The cost of each pear = $120/80 =$1.5
The selling price of each pear =$20/10 =$2

The profit percent = (2-1.5 /1.5 )x100%=33.33%

(2)Let the cost be X

The marked price =(1+40%)X =1.4X
The selling price=(1+40%)X*(1-10%)=1.4X*0.9=1.26X

The profit percent=(1.26-1)X*100%=26%

1)Herbert bought 80 pears at $120 and then sold all of them at $20 for 10.What was the profit or loss percent?

[20-(120/80)*10] / (120/80)*10 * 100%

=20-15 / 15 * 100%

=5 / 15 * 100%

=0.3(重複小數)% //


2)The marked price of an article is 40% higher than its cost and it is now sold at a discount of 10%.What is the profit percent?

(條問題本身有d問題...所以唔識...)

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