# 數學 [20點]

1) In an online photo album, 40% are landscapes, 35% are portraits and the rest are 50 still image photos

(a) Find the percentage of still image photos in the gallery

(b) Find the total number of photos

(c) If 20% of the portraits are children's photo, find the number of children's photo

2) In July, the price of a stock increased by 10%. In August, it fell by 15%. Te closing price of the stock in August was $65.45. Find

(a) the closing price of the stock in July,

(b) the closing price of the stock in June,

(c) the percentage change in the price of the stock from the end of June to the end of August

3) By selling a wallet for $120, a retailer loses $30. Find the percentage loss.

4) A personal digital assistant (PDA) socting $3600 is sold at a 28% loss. Find the selling price.

5) A computer wholesaler sold a hard drive to a retailer at a profit of 5%. The retailer sold it to a customer for $1050, at a profit of 25%. Find

(a) the retailer's buying price of the hard drive,

(b) the wholesaler's cost price of the hard drive,

(c) the wholesaler's percentage profit if he had sold the hard drive for $1050 directly to the customer.

6) Find the discount percent of each of the following

(a) Marked price = $85, selling price = $51

(b) Selling price = $1216, discount = $384

7) In a Christmas sale, a down jacket is sold at a 20% discount. The selling price is $1480

(a) Find the marked price of the down jacket

(b) If the down jacket were sold at a 36% discount, what would be its selling price ?

### 1 Answer

- 賣女孩的火柴Lv 71 decade agoFavorite Answer
1)

(a)

Percentage of still image photos

= 1 - (40% + 35%)

= 25% ...... (answer)

(b)

Total number of photos

= 50 ÷ 25%

= 50 x (100/25)

= 200 ...... (answer)

(c)

Number of children's photos

= 200 x 35% x 20%

= 14 ...... (answer)

2)

(a)

The closing price of the stock in July

= $65.45 ÷ (1 - 15%)

= $77 ...... (answer)

(b)

The close price of the stock in June

= $77 ÷ (1 + 10%)

= $70 ...... (answer)

(c)

The % change in the price of the stock from the end of Jun to the end of Aug

= [(65.45 - 70)/70] x 100%

= -6.5% ...... (answer)

3)

Marked price of the wallet

= $(120 + 30)

= $150

Percentage loss

= (30/150) x 100%

= 20% ...... (answer)

4)

Selling price

= $3600 x (1 - 28%)

= $2592 ...... (answer)

5)

(a)

The retailer's buying price of the drive

= $1050 ÷ (1 + 25%)

= $840 ...... (answer)

(b)

The wholesaler's cost price of the drive

= $840 ÷ (1 + 5%)

= $800 ...... (answer)

(c)

The wholesaler's % profit if he sold the drive directly to the customer

= [(1050 - 800)/800] x 100%

= 31.25% ...... (answer)

6)

(a)

Discount per cent

= [(85 - 51)/85] x 100%

= 40% ...... (answer)

(b)

Marked price

= $(1216 + 384)

= $1600

Discount per cent

= [384/1600] x 100%

= 24% ...... (answer)

7)

(a)

Marked price of the down jacket

= $1480 ÷ (1 - 20%)

= $1850 ...... (answer)

(b)

Selling price of the down jacket

= $1850 x (1 - 35%)

= $1202.5 ...... (answer)

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