Commodity profit = commodity price-commodity purchase price
Commodity profit rate = commodity profit ÷ commodity purchase price
(1) The purchase price of a sports shoe is 250 yuan. When sold at 10% off the list price, the profit margin is 15.2%. What's the list price of sports shoes?
Analysis: This question has the following equivalent relationship:
List price x90%= current selling price
(selling price-buying price) ÷ buying price x 100%= profit rate.
Solution: the price of sports shoes is X yuan, according to the meaning of the question:
(90% x-250)×250 = 15.2%
The equation can also be expressed by the equivalence relation of sales price-purchase price = profit:
90%x-250=250x 15.2%
To solve this equation, x=320.
The price of sports shoes is 320 yuan.
(2) 50 yuan, the original price of a commodity, was discounted by 10% due to poor sales, and then the price increased due to tight sales. The price of each commodity is 54 yuan. What is the percentage of increase?
Analysis: let the percentage of price increase be x, and the equivalence relation of this question can be expressed as:
Original selling price x90%x( 1+x)= current price.
Solution: the percentage of price increase is x, according to the meaning of the question:
50x90%x( 1+x)=54
To solve this equation, x=0.2, which means x=20%.
A: The percentage of price increase is 20%.
3. For a project, it takes 10 days for Party A to do it alone, and 15 days for Party B to do it alone. After four days, Party B will do the rest alone. How many days will it take?
Solution: Suppose it takes X days to complete.
According to the meaning of the question: (110+1/5) x4+115x =1.
Solution:
X=5
A: It will take five days to complete. In order to promote the newly listed X car, a shopping mall decided to let the buyers who bought the car on New Year's Day pay in four or two installments: once at the time of purchase, and the rest and its interest (annual interest rate of 5.6%) will be paid before New Year's Day next year. It is known that the price of each car is 82240 yuan. If the buyer pays exactly the same twice, how much should he pay each time?
Solution: Assume that each payment is X yuan. According to the meaning of the question, we can get:
x =(82240-x)5.6%-82240-x
Solution: x=42240
Answer: You have to pay 42,240 yuan each time.
-Fill in the blanks (2 points for each question, 20 points for * * *)
1。 The solution of equation 5X+4=4X-3 also conforms to equation 2X+M=2, then m = _ _ _.
2。 If X=-4 conforms to the equation kx-4=2x, then the algebraic expression (3K? +6K-8) is-.
3. If the algebraic expressions 7X-3 and 1/3 are reciprocal, the value of x is ———.
4. the equation about x (M+ 1)X? +2MX=0 is a linear equation with one variable, then m = _ _ _ _ _ _ and the solution of the equation is-.
5。 The solution of equation X=-X is-.
6。 A store promotes a certain brand of shirts, and now two promotion schemes are announced: the first one is to buy 10 pieces and give 1 piece; Please calculate the second discount of 10%, which scheme is more beneficial to customers? A: The first one.
7。 The sum of the numbers A and B is 1 12. If the number A is less than 3 times 4 of the number B, then the number A is-.
8。 Divide 150 into two numbers, and the ratio of the two numbers is 3:7. So these two numbers are.
9。 The purchase price of a commodity is X yuan per piece, and the retail price is 900 yuan. In order to adapt to the market competition, the store reduced the price of 10% of the retail price and sold it in 40 yuan, so that the profit margin could reach 10% and the purchase price was-.
10。 A three-digit number, where the single digit is X, the hundredth digit is larger than the single digit 1, and the tenth digit is smaller than the single digit 1, then these three digits are-.
Second, multiple-choice questions (3 points for each question, ***33 points)
1 1。 Divide both sides of the equation -8X=2 by -8 to get (-).
a，X=-4 - B，X= 1/4，......c，X=4.....d，X=- 1/4
12, which of the following transposition is correct (_ _ _).
I from 5+X= 12, x = 5+ 12..........b, 7x = 4x-3, 7X-4X=3.
10x = 1 1 1 1x =-2...d，x-5 = 4x+2。
13. The correct way to solve equation 3-(3X-5)/2=-(X+ 1)/7 is (-).
a，3-7(3X-5)=-2(X+ 1)........B.42-2 1X-5=-2X+ 1...........c，42-2 1X+35=-2X-2.......d，42-2 1X-35=-2X+2
(14) If the value of algebraic expression (3k+5)/7 is 2, then k should be equal to.
(
)
One,-1
b， 19/3
c，7/3
d，3
(15) If the values of algebraic expressions 8x-7 and 6-2x are reciprocal, then x
The value of is.
(
)
a，X=- 13/ 10
b，X=- 1/6
c，X= 1/6
d，X=3/ 10
(17) There is an old fable that donkeys and mules walk together. They carry different bags of goods, each of which is the same weight. The donkey complained that the burden was too heavy. The mule said, "Why are you complaining?" If you give me a bag, I will bear twice your weight; If I give you a bag, we will bring the same amount! "So the donkey first pack number is
Answer, 5
b，6
c，7
d，8
(18) Use a coil to make a rectangle with a length of 24 and a width of 12. If converted into a square, the area of this square is
(
)
I. 8 1
b8
c，324
d，326
(19) If you want a commodity to return to its original price after a price increase of 25%, you should reduce the price.
(
)
15%
Twenty percent
c，25%
d，40%
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