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I bought a pen, notebook, stationery and schoolbag in the mall
Stationery includes pen and schoolbag, so I bought pen, notebook and schoolbag in the mall
We need 35 pens with a unit price of 2 yuan. Wenhai pen shop: buy 6 pens and get one free. Stationery store: all goods are 10% off
Department store: 50 yuan, 20% discount. Which one is the best?
Wenhai Bizhuang: buy 6 free one, a total of 35, so buy 30 free 5, need 2 * 30 = 60 yuan
Stationery store: 10% off, 2 * 35 * 0.9 = 63 yuan
Department store: I'm not sure what it means. 2 * 35 * 0.8 = 56 yuan if it's 50% off, 50 * 0.8 + (2 * 35-50) = 60 yuan if it's 50% off
The stationery counter in the shopping mall bought a batch of "hero" brand pens at the price of a (a as an integer) yuan, and decided to increase the price by 2 yuan for each pen. Due to the excellent price, good quality and beautiful appearance of these pens, they sold out quickly. When checking out, the salesperson found that the total sales amount of these pens was (399a + 805) yuan, Based on the above information, can you find out the total number of pens purchased at the stationery counter and the purchase price of each pen?
( ⊙o⊙
If x pens are purchased, they are:
399a+805=aX+2X,
X=(399a+805)/(a+2)=[399(a+2)+7]/(a+2)=（399+7/(a+2)
Because a is an integer and X is an integer, a = 5,
X = 400
A mobile communication company has set up two kinds of communication services, "global link": the user pays 50 yuan monthly rent first, and then pays 0.4 yuan for each minute of the call; "Express link": no monthly rent is paid. For each minute of the call, the user pays 0.6 yuan (1) how many minutes of the call in a month, The cost of two kinds of mobile communication is equal. (2) which is the best way for someone to estimate the cost of one month and 300 minutes. (3) write the relationship between y1.y2 and X
1. Set up a call for X minutes
50+0.4x=0.6x
0.2x=50
x=250
2. The first way: 50 + 0.4 × 300 = 50 + 120 = 170
The second way: 0.6 × 300 = 180
The first way is cost-effective
3、y1=50+0.4x
y2=0.6x
If the area of the diamond ABCD is 24 square centimeters, and the diagonal AC ratio BD is 1:3, what is the side length of the diamond
In this way, let AC = x, BD = y, according to the area of the diamond is 24, we get 0.5 × x × y = 24 ①, the diagonal AC is 1:3, so y = 3x ② according to the two formulas of ① and ②, we get x = 2 √ 2, y = 6 √ 2, because the diagonals of the diamond are perpendicular to each other and equally divided, so the side length = √ [(0.5x)? + (0.5y)?] = √ (2 + 18) = 2 √ 5
Solve the equation (the square of x-6x-2 = 0)
The square of x-6x-2 = 0
x^2-6x=2
(x-3)^2=2+3^2
(x-3)^2=11
X-3 = positive and negative root sign 11
X1 = radical 11 + 3 x2 = - radical 11 + 3
A and B vehicles leave from ab at the same time and meet at 6km away from the midpoint. It is known that the speed of a vehicle is five sixths of that of B vehicle. How many meters is ab away
The other people's answer is 6 times 2. Who can explain why to me
When you draw a line diagram, you can see at a glance: 6 × 2 = 12 km, which means that the express train runs more than the local train. The express train runs 6 / 11 of the whole journey, while the local train runs 5 / 11, with a difference of 6 / 11-5 / 11 = 1 / 11
So 12 △ 1 / 11 = 132 km
Do you understand?
There are also simple calculations:
6÷（6/11-1/2)
=6÷1/12
=132 km
It is known that the circumference of isosceles triangle is 16cm, one side is 5cm long, and the other two sides are equal to several
5cm is the bottom time
The other two sides are equal to: (16-5) △ 2 = 5.5cm
5 cm is waist time
Bottom = 16-5 × 2 = 6cm
If a, B and C are three arbitrary integers, how many integers will there be among a + B2, B + C2 and C + A2? Please use the parity of integers to explain the reason
There will be at least one integer. According to the parity of integers, three cases can be determined: odd + even = odd, if divided by 2, it is not equal to the integer. Odd + odd = even, if divided by 2, it is equal to the integer. Even + even = even, if divided by 2, it is equal to the integer Four cases: all odd numbers: then a + B divided by 2, B + C divided by 2, C + a divided by 2, all integers are even numbers: then a + B divided by 2, B + C divided by 2, C + a divided by 2, all integers are odd and even numbers: then a + B divided by 2, B + C divided by 2, C + a divided by 2, an integer is even and odd numbers: then a + B divided by 2, B + C divided by 2, C + a divided by 2, an integer is odd and even numbers
Practical problems of tree planting
There is a road with a length of 2000 meters. A lamp post is buried 50 meters apart on both sides of the road. How many lamp posts do you need to buy from the beginning to the end?
Because 2000 / 50 = 40
So from the beginning to the end, we need to bury street lamp poles = 40 + 1 = 41
RELATED INFORMATIONS
- 1. 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
- 2. Buy 3 pens in a stationery shop and get 2 free pens, 4 yuan each. How much should I pay for 12 pens?
- 3. 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
- 4. 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?
- 5. 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?
- 6. 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?
- 7. 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?
- 8. 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
- 9. 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?
- 10. 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)
- 11. In order to promote a commodity with the same price, supermarket a, supermarket B and supermarket C cut prices by 20% twice in a row, 40% at a time in supermarket B, 30% at the first time in supermarket C and 10% at the second time. Which supermarket is more cost-effective for customers to buy this commodity A. B. B. C. C. D
- 12. In order to promote a product priced at M yuan, supermarket a, supermarket B and supermarket C cut prices by 20% twice in a row, 40% at a time in supermarket B, 30% at the first time in supermarket C and 10% at the second time. At this time, the most cost-effective supermarket for customers to buy this product is () A. A B. B C. C D. B or C
- 13. Every day, the supermarket bought back a batch of T-shirts from other places with 50000 yuan. Due to the good sales, the mall urgently allocated 186000 yuan to buy back T-shirts that were twice as much as the first time. However, the second time was 12 yuan more expensive than the first time. The mall sold them at the price of 80 yuan. In order to shorten the inventory time, the last 400 T-shirts were sold out at a discount of 6.5% How much is the profit of the Communist Party of China?
- 14. A supermarket used 80000 yuan to purchase a batch of "T-shirts" from other places. Due to the good sales, the supermarket urgently allocated 176000 yuan to purchase "T-shirts" which are twice as much as the last time. However, the second purchase price is 4 yuan more than the first purchase price. The supermarket sells them at 58 yuan per piece, and the remaining 150 pieces are sold out at a 20% discount. How much money has the supermarket made in this business (including two purchases)?
- 15. Xiaoying and several students went to the stationery store to buy exercise books. The stationery store stipulated that if the purchase reached a certain quantity, they could buy them at the wholesale price. So they gathered together 60 yuan to buy them at the wholesale price. In this way, the number of exercise books purchased was 30 more than that purchased at the retail price. If the wholesale price of each exercise book was 45 times of the retail price, what was the retail price of each exercise book How much is it?
- 16. A school logistics staff to a stationery shop to buy test stationery bags for ninth grade students, stationery shop rules a purchase of more than 400, can enjoy a 20% discount. If you buy a ninth grade students, can not enjoy a 20% discount, need to pay 1936 yuan; if you buy 88, can enjoy a 20% discount, also only need to pay 1936 yuan. How many ninth grade students in the school ？
- 17. Xiao Ming and Xiao Gang collect digital cards. Xiao Ming's cards account for 16 / 11 of the total. If he gives 15 cards to Xiao Gang, they will have the same number. How many cards do they have in total?
- 18. At the school sports meeting, in the 200m sprint, Xiaoqiang took 2 / 3 minutes, Xiaogang took 50 seconds and Xiaoming took 0.6 minutes. Which of them is the fastest?
- 19. It took Xiaoming 18 seconds to run 100 meters and Xiaogang 24 seconds to run 150 meters. Who runs fast? process
- 20. Xiao Gang and Xiao Ming are in the 100 meter race. When Xiao Gang runs 80 meters, Xiao Ming is 40 meters away from the end. Then when Xiao Gang runs to the end, how many meters is Xiao Ming away from the end?