form1maths

2008-03-26 10:14 pm

1.the selling price of a handbag is $2100.The profit percent is 16 2/3%.What is the cost price of the handbag?
2.If a man sells a chair at $285,then the loss percent is5%.Find his profit percent if he increases the selling pricce by 20%
3.John spent 20% of his money yesterday. He spends 25%of the remainder today.If he has $30 left,how much did he have at first?

回答 (1)

用戶141121

2008-03-26 10:36 pm

✔ 最佳答案

1. $2100/(1+16 2/3%)
=$2100/(1+ 50/3%)
=$2100/(1+50/300)
=$2100/(350/300)
=$2100/(7/6)
=$2100 x 6/7
=$1,800

2. Cost of the chair = $285/(1-5%)
= $285/95%
= $285/(95/100)
= $285/(19/20)
= $285 x 20/19
= $300
New selling price = $285 x (1+20%)
= $285 x 120/100
= $285 x 6/5
= $342
Profit Percentage = ($342 - $300)/$300 x100%
=$42/$300 x100%
=$7/$50 x 100%
= 14%

3. Let y be the amount of money he had at first
y (1-20%) (1-25%) = $30
y (80%) (75%) = $30
0.6y = $30
y = $50

4. x (1+5%) = 315
x (105%) = 315
1.05x=315
x = 300

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