There are 12 products, one of which is unqualified. Give you a weightless balance. Can you find out which unqualified product is only three times and judge whether it is lighter or heavier than the genuine product?
The medicine contains 10 box, each box contains 10 box, and each box contains 100 capsules. The genuine product is per capsule 1 g, of which 1 box of defective products is only 0.9 g per capsule. There is a very sensitive weighing machine. How can we find out which box the defective product is when we can only weigh 1 time?
The medicine contains 10 box, each box contains 10 box, and each box contains 100 capsules. Genuine products per capsule 1g, and several boxes of defective products are only 0.9g per capsule. There is a very sensitive weighing machine. How can I find out which boxes are defective when I can only say 1 time?
If you have any math problems to test your brain, give the answers. Master Wang sells shoes. A pair of shoes was bought in 30 yuan and sold in 20 yuan. The customer came to buy shoes and gave a 50. Master Wang had no change, so he asked his neighbor to change to 50 yuan. Afterwards, the neighbors found out that the money was fake, and Master Wang paid 50 yuan back to the neighbors. How much did Master Wang lose? (This question is not simple, 99 out of 100 people will miscalculate) How much did they lose?
Answer: the loss is 60.
About the brain math problem ~ 5 kg of litchi equals 2 kg of longan, 8 kg of longan =20 kg of litchi has 6 kg of litchi, so litchi =3 12÷(20+6)= 12 longan = 12×5÷2=30.
What are the high school math problems? What are the classic high school math problems? The questions are very detailed and basic, which can prevent the phenomenon of superiority, but there are many problems that can be done selectively.
What is a good math problem? 1. Use a rectangular piece of paper with a length of 20cm and a width of 12.56cm to form a cylinder, and the lateral area of the cylinder is () square centimeters. If the height of the cylinder is 20 cm, the diameter of the bottom of the closed cylinder is () cm. 2. When deriving the formula of cone volume, the cylinder and cone () and () we selected are all equal. When the formula is derived from the cone through experiments, the cylinder and cone () and () we choose are all equal. The cone volume formula derived from the experiment is expressed by letters as (). 3. The diameter of the bottom of the cylinder is 4cm and the height is10cm. Its bottom area is () square centimeters, lateral area is () square centimeters, its surface area is () square centimeters and its volume is (). 4. The diameter and height of the cylinder bottom are 2 microns. If it is cut into two identical small cylinders, the surface area will increase by () square decimeter, and the volume of each small cylinder is () cubic decimeter. 5. Two cylinders and cones with equal bottoms and heights, their volume sum is () 20 cubic centimeters, the volume of the cylinder is () cubic centimeters, and the volume of the cone is () cubic centimeters. 6. A section of iron cylindrical sewer pipe is 2 meters long, with a bottom radius of 2.5 decimeters and a joint of 2 centimeters. It takes at least 20 square decimeters of iron to make this section of sewer pipe. Answer: Use a rectangular piece of paper with a length of 20cm and a width of 12.56cm to form a cylinder. The side area of the cylinder is (25 1.2) square centimeters. If the height of the cylinder is 20cm, the diameter of the bottom of the closed cylinder is (4) cm. 2. When we derive the cone volume formula, the cylinder and cone (base circle radius) and (height) we choose are equal. When we derive the formula for deriving the cone through experiments, the cylinder and cone (base area) and (height) we choose are equal. The formula of cone volume derived from experiments is expressed in letters as (v = 1/3sh). 3. The diameter of the bottom of the cylinder is 4cm and the height is10cm. Its bottom area is (12.56) cm2, lateral area is (125.6) cm2, its surface area is (150.72) cm2 and its volume is (12) cm2. 4. The diameter and height of the cylinder bottom are 2 microns. If cut into two identical small cylinders, the surface area will increase by (6.28) square decimeter, and the volume of each small cylinder is (3. 14) cubic decimeter. 5. Two cylinders and cones with equal bottoms and heights, their volume sum is () 20 cubic centimeters, the volume of the cylinder is (15) cubic centimeters, and the volume of the cone is (5) cubic centimeters. 6. A section of iron cylindrical sewer pipe is 2 meters long, with a bottom radius of 2.5 decimeters and a joint of 2 centimeters. At least (3 18) square decimeter of iron is needed to manufacture this section of sewer pipe. Question: 1, in 2007 1 1, Xiaoming deposited 4,000 yuan in the bank and chose lump-sum deposit and withdrawal for three years, with an annual interest rate of 5.22%. How much interest does Xiao Ming get after deducting 5% interest tax at maturity? How much money can Xiaoming get back from the bank? 2. In September 2007, Xiao Ming deposited 500 yuan pocket money in the bank for a fixed period of one year. After the expiration of the preparation period, the after-tax interest will be donated to the "Hope Project". If the annual interest rate is 3.87% and the interest tax rate is 5%, how much can the nickname donate when it expires? 3. Calculated by the charged deposit interest rate: A uses 2000 yuan to deposit for one year, and then deposits with interest for one year after maturity; B saved it directly for two years with 2000 yuan. Which deposit method earns more interest after maturity? Answer: 1, 4,000 * 5.22% * 3 * (1-5%) = 595.08 (yuan) 4,000+595.08 = 4,595.08 (yuan) Answer: Xiaoming got interest of 595.08 yuan from the bank. 2.500*3.8%=28 (yuan) 28- 1.4=26.6 (yuan) A: Xiaoming can donate 26.6 yuan when due. 3. A: [2000+2000 * 3.87% * (1-5%)] * 3.87% * 95% ≈ 76 (yuan) B: 2000*4.50%*95%=85.5 (yuan).
There are three people who go to 30 yuan for a night. Each of them paid 10 yuan enough. 30 yuan gave it to the boss. Later, the boss said that 25 yuan was enough for today's discount, so he took out the 5 yuan and asked the waiter to return it to them. The waiter secretly hid 2 yuan's money, and then distributed the rest of 3 yuan's money to three people, each at 1 yuan. At the beginning, everyone paid 10 yuan, and now it is returned to 1 yuan, which means 10- 1 = 9. Everyone only spent 9 yuan's money, three people spent 9 yuan, 3×9 = 27 yuan+2 yuan hidden by the waiter =29 yuan. Where did the dollar go? Please give a reasonable explanation!
Do you have a brain teaser math problem? I recommend you to watch a movie called Extreme Space, which contains the math problems you want. Great! Hope to adopt
What is a short and complicated math problem1+1+1* 2+3 * 5+6+7+9+10+201? What is the answer to this formula?
Are there any interesting and simple math problems? Three-digit black hole 495:
As long as three digits are entered, the required digits are different, such as 1 1 1, 222, etc. Then you rearrange the three numbers of this three-digit number according to the size to get the maximum number and the minimum number, subtract them to get a new number, rearrange them according to the above method, and subtract them again to finally get the number 495.
For example: input 352, maximum digit 532, minimum digit 235, subtraction 297; Rearrange it into 972 and 279, and subtract it to get 693; Then arrange 963 and 369, subtract 594; Finally, the arrangement of 954 and 459 is subtracted to get 495.
The most brain-burning math problem in the world. 90% is wrong? The hardest thing in the world is actually "1+ 1". Don't laugh and don't think I'm lying to you. Actually, it's true. No one has been able to solve this problem since ancient times. Goldbach conjecture.
1742 On June 7th, German amateur mathematician Goldbach wrote to the great mathematician Euler at that time, and put forward the following conjecture:
(a) Any even number of n 6 can be expressed as the sum of two odd prime numbers.
(b) Any odd number of n 9 can be expressed as the sum of three odd prime numbers.
This is the famous Goldbach conjecture. Since Fermat put forward this conjecture, many mathematicians have been trying to conquer it, but they have not succeeded. Of course, some people have done some specific verification work, such as:
6 = 3 + 3,8 = 3 + 5, 10 = 5 + 5 = 3 + 7, 12 = 5 + 7, 14 = 7 + 7 = 3 + 1 1,
16 = 5+11,18 = 5+13, ...
Someone looked up even numbers within 33× 108 and greater than 6, and Goldbach conjecture (a) was established. However, the mathematical proof of lattice has yet to be completed by mathematicians. At present, the best result is proved by Chinese mathematician Chen Jingrun in 1966, which is called Chen Theorem. "Any large enough even number is the sum of a prime number and a natural number.
Before Chen Jingrun, the progress of even numbers can be expressed as the sum of the products of S prime numbers and T prime numbers (referred to as the "s+t" problem) as follows:
1920, Bren of Norway proved "9+9".
1924, Rademacher proved "7+7".
1932, Esterman of England proved "6+6".
1937, Ricei of Italy proved "5+7", "4+9", "3+ 15" and "2+366" successively.
1938, Byxwrao of the Soviet Union proved "5+5".
1940, Byxwrao of the Soviet Union proved "4+4".
1948, Hungary's benevolence and righteousness proved "1+c", where c is the number of nature.
1956, Wang Yuan of China proved "3+4".
1957, China and Wang Yuan successively proved "3+3" and "2+3".
1962, Pan Chengdong of China and Barba of the Soviet Union proved "1+5".
Wang Yuan of China proved "1+4".
1965, Byxwrao and vinogradov Jr of the Soviet Union and Bombieri of Italy proved "1+3".
1966, China Chen Jingrun proved "1+2".
Who will finally overcome the problem of "1+ 1"? It is still unpredictable.