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Xiao Ming bought three kinds of stationery: pencil, eraser and exercise book. It is known that their numbers are different prime numbers and satisfy the equation: number of pencils * (number of pencils + eraser)
Xiao Ming bought three kinds of stationery: pencil, eraser and book. It is known that their numbers are different prime numbers, and satisfy the pencil number x (eraser number + book number) = 110 + book number. Question: Xiao Ming bought () erasers. It is not difficult to solve this problem, but the difficult point is the entry point. This problem provides two important conditions: first
Xiao Hong bought 5 ballpoint pens and 3 pencils at the stationery store, which cost 2.90 yuan. It is known that each pencil costs 0.30 yuan. How much is each ballpoint pen?
(2.90-0.30 × 3) △ 5, = (2.90-0.90) △ 5, = 2 △ 5, = 0.4 (yuan); answer: each ballpoint pen is 0.4 yuan
Xiao Ming went to a stationery store to buy pencils and erasers for 30 students in the school art activity group
Xiao Ming went to a stationery store run by wholesale and retail businesses to buy pencils and erasers for 30 students in the art activity group of the school. According to the rules of the store, if you buy 2 pencils and 1 eraser for each of the group, you must pay 39 yuan at the retail price; if you buy 3 lead pens and 2 erasers for each of the group, you can pay 39 yuan at the wholesale price, It is known that the wholesale price of each pencil is 0.1 yuan lower than the retail price, and the wholesale price of each rubber is 0.25 yuan lower than the retail price. How much is the wholesale price of each pencil and rubber in this shop?
If the wholesale price of pencil is X Yuan and the wholesale price of rubber is y yuan, then the retail price of pencil is x + 0.1 yuan and the retail price of rubber is y + 0.25 yuan
30*(2(x+0.1)+y+0.25)=39
30*( 3x+2y)=42
The solution of the equations is x = 0.3, y = 0.25
A: the wholesale price of each pencil and rubber in this shop is 0.3 yuan and 0.25 yuan respectively
（5*11x－10）/（11x）＝（5×7x＋10）/（7x＋4）
（5*11x－10）/（11x）＝（5×7x＋10）/（7x＋4）
Extract the common factor to get [5 (11x - 2)] / (11x) = [5 (7x + 2)] / (7x + 4)
Divide both sides by 5 to get (11x - 2) / (11x) = (7x + 2) / (7x + 4)
Remove the denominator to get (11x - 2) (7x + 4) = (7x + 2) (11x)
Remove brackets to get 77X & # 178; + 44x - 14x - 8 = 77X & # 178; + 22x
It is reduced to x = 1
Simple calculation by factorization 2 * 101 ^ 2-2 * 101 * 102 + 2 * 51 ^ 2
A:
2*101^2-2*101*102+2*51^2
=2*(101^2-101*102+51^2)
=2*(101^2-2*101*51+51^2)
=2*(101-51)^2
=2*50^2
=2*2500
=5000
In the triangle ABC, the points D and E are on the edge BC, the angle BAE = angle CAD, the angle ade = angle AED
Syndrome: according to the sum of the internal angles of triangles is 180 degrees, the following results are obtained
Angle CAD + angle ade + angle c = 180 degree
Angle BAE + angle AED + angle B = 180 degree
Because: angle CAD = angle BAE
Angle ade = angle AED
So: angle B = angle C
How many centimeters are one foot, one inch and one foot?
In Han Dynasty, one foot equals 23.1 cm, in Wei and Jin Dynasties, 26.7 cm in Sui and Tang Dynasties, and 30.72 cm in song and Yuan Dynasties
Ten feet is one foot
Ten inches make a foot
It is generally believed that:
One foot = 333.333cm
One foot = 33.3333 cm
1 inch = 3.333 cm
A rectangular playground is 60 meters long and 30 meters wide. Draw its plan with a scale of 1:1000
Hello, Hanying. Warm for you
On the picture
60m = 6000cm
30 m = 3000 cm
Length: 6000 × 1 / 1000 = 6cm
Width: 3000 × 1 / 1000 = 3cm
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How to prove that the sum of squares of the lengths of three middle lines of a triangle is equal to 3 / 4 of the sum of squares of the lengths of three sides
1. The square of a - the square of X + 2x-1 = the square of a - ()
2. Square of X - (square of Y - x + y) = square of X - square of Y + ()
3.（2a-b+c）（2a+b-c）=【2a-（ ）】【2a+（ ）】
1. The square of a - the square of X + 2x-1 = the square of a - (X & # 178; - 2x + 1)
2. Square of X - (square of Y - x + y) = square of X - square of Y + (X-Y)
3.（2a-b+c）（2a+b-c）=【2a-（ b-c ）】【2a+（ b-c ）】
RELATED INFORMATIONS
- 1. Li Ming went to the stationery store to buy pencils and erasers for 30 students in the school's art group. It is known that each pencil costs m yuan, and each eraser costs n yuan For two pencils and three erasers, the total payment is RMB
- 2. The stationery store brought in 10 boxes of watercolor pens and 10 boxes of erasers. It costs 4 yuan less to buy watercolor pens than to buy erasers. Each box of watercolor pens costs 8.5 yuan. How much is each box of erasers? Equation! Write the equality!
- 3. According to the price of the stationery box is two fifths less than that of the schoolbag, fill in the quantity relation
- 4. Xiaoju spent 50 yuan to buy a schoolbag and a pencil case. The price of the pencil case is one ninth that of the schoolbag. How much did she spend to buy a schoolbag
- 5. The price of a schoolbag is 36 yuan more than that of a pencil case, which is three times as much as that of a pencil case. How much is a schoolbag and a pencil case
- 6. The price of two different schoolbags sold by the store is 60 yuan. According to the cost, one of them lost 1 / 4 and the other earned 1 / 4. Did they earn or lose money when they were sold? Why
- 7. Xiaoming, Xiaolan and Xiaogang each have some balls. For example, after Xiaoming gives Xiaolan 10 balls and Xiaolan gives Xiaogang 6 balls, the three have the same number of balls. Ask Xiaolan more than Xiaogang less
- 8. A document needs to be printed. It takes 2 hours for Xiao Ming to do it alone, 2.4 hours for Xiao Gang to do it alone, 3 hours for Xiao Lan to do it alone, and 36 minutes for Xiao Ming and LAN to work. Xiao Ming has to leave, and Xiao Gang works for him. How long does it take to finish it?
- 9. On July 1st, Fangfang and Mingming went to the library to read books together. What day is the next time to go to the library? Fangfang: I go to the library every five days Mingming: I go every six days
- 10. A, B and C often go to the library to read books. A goes once every three days, B goes once every four days and C goes once every five days. On August 2, they all went to the library So what month and day did they meet again in the library?
- 11. Xiao Ming bought several pencils at the price of 1 yuan and 3 pencils, and sold them all at the price of 2 yuan and 5 pencils. If he made 10 yuan, do you know how many pencils he sold?
- 12. Each pencil is 0.9 yuan, 2 yuan, 3 yuan, 4 yuan, 5 yuan. Which pencil is cheaper? The number of people who want to score is limited, only one, and those who want to score will come quickly
- 13. A shopping mall can make a profit of 2 yuan for each stationery. In order to support the poor mountainous areas, it is now sold to a mountainous school at a 70% discount of the original price. As a result, the profit of each stationery is 0.2 yuan (profit = selling price purchase price). How much is the purchase price of each stationery?
- 14. The number of pencils in the stationery shop is twice that of pens. Every day, 15 pens and 20 pencils are sold out. After a few days, there are still 80 pencils left. How many pens and pencils are there in the stationery shop?
- 15. At the stationery counter of a store, if 16 pencils are sold, the ratio of the number of pencils left to the number of pens is 1:3. If 52 pens are sold again, C At the stationery counter of a store, if 16 pencils are sold, the ratio of the number of pencils left to the number of pens is 1:3. If 52 pencils are sold, the ratio of the number of pencils left to the number of pencils is 2:5. How many pencils are there?
- 16. The stationery store bought 18 boxes of stationery today, including 540 pens and 840 erasers. If the number of erasers in each box is the same as that of pens, how many erasers are there?
- 17. The school plans to buy 40 pens and some notebooks (the number of notebooks exceeds the number of pens). The price of both a and B plus the stationery shop is 10 yuan for each pen and the number of notebooks It's 2 yuan per book. The preferential way of shop a is 10% off for pens and 20% off for notebooks. Shop B's preferential way is to give one notebook for every five pens. Pens are not discounted, and notebooks are 7.5% off. So how to buy more cost-effective (please see the title and come back) good bonus points
- 18. Buy 3 pens in a stationery shop and get 2 free pens, 4 yuan each. How much should I pay for 12 pens?
- 19. The stationery store bought 100 pens at the price of 4 yuan each, and each pen was sold at 6 yuan. When some pens were sold, the remaining pens were sold at a 10% discount. When all pens were sold, the store made a total profit of 188 yuan. How many pens were sold at a 10% discount? Don't use the equation, but use the formula
- 20. I bought a pen, notebook, stationery and schoolbag in the mall