盈利/虧蝕百分率!快!!!

2012-08-04 5:55 pm

1:George bought a bicycle at a discount of 11%,and he saved 99$.Find the market price and selling price of the bicycle.

2:A dozen fountain pens are sold at a loss of 7.5% and the loss is $180.Find the cost price of each fountain pen.

3:In a plane,4% of the seats are first calss,16% are business class and the rest are economy class.There are 240 economy class seatS.
3a:Find the total number of seats in the plane.

3b:Find the number of first class seats in the plane.
3c:If 20 economy class seats are removed,What percentage of the seats are first class?

回答 (1)

經數學人

2012-08-04 9:22 pm

✔ 最佳答案

1. Let X be the market price.
X x 11% = $99
X = $99 / 0.11
X = $900
Selling price = $900 - 99 = $801

2.
Let X be the cost of a dozen pens.
X x 7.5% = 180
X = 180 / 0.075
X = $2400
cost price of each = $2400/12 = $200

3
a) Let X be the total number of seats
X x (1 - 4% - 16%) = 240
X = 240 / 0.8
X = 300

b) 300 x 4% = 12

c) 12 / (300 - 20) = 4.29%

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