幫手計數(7題)(急)(20分)

1.
(a)
The discount
= $1800 x 40%
= $720
(b)
The selling price of the carpet
= $1800 x (1 - 40%)
= $1800 - $720
= $1080

2.
The marked price of the trousers
= $96 / (1 - 25%)
= $128

3.
The marked price of the basketball
= $12 / 15%
= $80

4.
(a)
The marked price of the watch
= $140 / (1 - 30%)
= $200
(b)
The discount
= $200 - $140
= $60

5.
(a)
The selling price of the coat
= $1250 x (1 - 60%)
= $1250 x 40%
= $500
(b)
The discount percent
= [($1250 x 60% + $100) / $1250] x 100%
= [($750 + $100) / $1250] x 100%
= ($850 / $1250) x 100%
= 0.68 x 100%
= 68%

6.
Let the marked price of a pen be $x.
(12x) (45%) = 27
12x = 60
x = 5

The selling price of a pen
= $5 x (1 - 45%)
= $5 x 55%
= $2.75

7.
The discount percent
= [(5 - 4) / 5] x 100%
= (1/5) x 100%
= 20%

If there is any mistake, please inform me.

1.The marked price of a carpat was $1800.It was sold at a discount of 40%.
(a)What is the discount?

discount amount = marked price * discount = 1800 * 40% = $720

(b)Find the selling price.

selling price = marked price - discount amount = 1800 - 720 = $1080

2.Tom bought a pair of trousers for $96 at a discount of 25%.Find the marked price of the trousers.

Let the marked price be x
new price = marked price * (1 - discount)
96 = x * (1 - 25%)
x = 128
so the marked price is $128

3.Davis saved $12 by buying a basketball at a 15% discount.What was the marked price of the basketball?

Davis saved $12, so the discount amount = 12
Let the marked price of the basketball be x
discount amount = marked price * discount
12 = x * 15%
x = 80

4.Cindy paid $140 for a watch which was sold at a 30% discount.
(a)Find the marked price.

Let the marked price be x
new price = marked price * (1 - discount)
140 = x * (1 - 30%)
x = 200
so the marked price is $200

(b)What was the discount?

discount amount = marked price - discounted price
= 200 - 140 = 60
so the discount amount = $60

5.Cathy bought a coat which was marked $1250 at a 60% discount.
(a)Find the selling price.

selling price = marked price * (1 - discount)
= 1250 * (1 - 60%)
= 500
so the selling price = $500

(b)If Anna got an extra discount of $100 for the same coat,find the discount percent Anna got.

the new selling price = 500 - 100 = 400
the percent change = (new price - old price)/(old price) * 100%
= [(400 - 1250)/1250] * 100%
= -68%
so the discount percentage = 68%

6.Peter bought a dozen of pens at 45% discount ans saved $27.Find selling price of each pen.

Let the marked price of a dozen of pens be x
discount amount = marked price * discount
27 = x * 45%
x = 60
so the marked price of each pen is 60/12 = $5

7.A hotel gives a special offer for the buffer dinner.For every 5 persons who enjoy the buffet dinner,one of them will get it free.Find the discount percent.

Let the price of buffer dinner be x
old price of buffer dinner for 5 persons = 5x
discounted price of buffer dinner for 5 persons = 4x
percentage change = (new price - old price)/(old price) * 100%
= (4x - 5x)/ (5x) * 100%
= -20%
so the discount percentage is 20%

希望幫到你

1. marked price = $1800
(a) discount = $1800 x 40% = $720
(b) selling price = $1800 - $720 = $1080

2. selling price = $96
marked price = $96/(1-25%) = $128

3. saving = $12
marked price = $12/15% = $80

4. selling price =$140
(a) marked price = $140/(1-30%) = $200
(b) discount = $200 - $140 = $60

5. marked price = $1250
(a) selling price to Cathy = $1250 x (1-60%) = $500
(b) selling price to Anna = $500 - $100 = $400
discount = (1250-400)/1250 = 68%

6. saving of each pen = $27/12 = $2.25 = discount
selling price of each pen = ($2.25/45%) x 55% = $2.75

7. The discount % = 100% -(4/5 x 100%) = 20%

1a 1800x40% =720
1b.1800-720=1080

2. 96/(1-25%) =128

3.x X 15%=12
x=80

4a.140/(1-30)=200
4b 140x30%=42

5a.1250x(1-40%)=750
5b. 唔識