Math homework...again~(急!10點!!!!!!)

1. The selling price of the jewellery
=100000*(1-22.5%)
=100000*77.5%
=$77500

2. The selling price of each pencil
=36/12*(1+40%)
=3*140%
=$4.2

3. The profit percent
= 20-1200/100除以1200/100*100%
=8/12*100%
=66有2/3%

1) 100000 * (1- 22.5%)
= 100000*0.225
= 22500
2) 36/12*(1-40%)
=1.8
3) [20-(1200/100)]/20*100%
=40%

2006-12-12 20:55:24 補充：
Question 2 is wrong2) 36/12*(1+40%) =4.2

1. the selling price of the jewellery is,
$100000*(1-0.225)
=$77500

2. the selling price of each pencil is,
$36*(1+40)/12
=$4.2

3. let the profit percent be p ,
$1200*(1+p)/100=20
p=0.666( correct to d.p. 3)

1.100000-(100000x22.5%)=77500
2.(36x40%+36)/12=4.2
3.式唔知 a:40%

1.) $100000 *(1-22.5%)
=$100000*77.5%
=$77500

2.) $36 *(1+40%)
=$50.4

3.) old price(each)=1200
new price(each)=100*20=2000
%change=(2000-1200)/1200*100%
=66.7%
the profit percent =66.7%

1.) Miss Chan bought a set of jewellery at $100000 and sold it at a loss of 22.5%.Find the selling price of the jewellery.

$100000*(1-22.5%)
=$100000*0.775
=$77500

2.) Kenneth bought a dozen of pencils at $36 and sold them at a profit of 40%.What was the selling price of each pencil?

The selling price of a dozen of pencils is:
$36*(1+40%)
=$36*1.4
=$50.4
The selling price of each pencil is:
$50.4/12
=$4.2

3.) Wilson bought 100 books at $1200 and sold them at $20 each.Find the profit percent.

The income that Wilson got:
100*$20
=$2000
Profit percent:
(2000-1200)/1200*100%
=800/1200*100%
=66.67%(2sig.fig)