Since April 1, 2009, China Railway has implemented a new train diagram. According to the new diagram, the biggest adjustment is made for passenger trains, and the running speed of some of them will be greatly shortened. It is estimated that the one-way direct running time of a high-speed train between city a and city B will be half an hour. During a test run, the running time of the test train from city a to city B will be shortened It takes 6 minutes more than the expected time, and the driving time from city B to city a is the same as the expected time. If the average driving time from city B to city a is 40 kilometers more than that from city B, what is the average speed from city a to city B?

Suppose that the average speed from city a to city B is x kilometers per hour, then the average speed from city B to city a is (x + 40) kilometers per hour

RELATED INFORMATIONS

1. Given - 1 < B < 0,0 < a < 1, then in the algebraic formula A-B, a + B, a + B & # 178;, a & # 178; + B, for any a and B, the maximum value of the corresponding algebraic formula is () （A）a+b （B）a-b （C）a+b² （D）a²+b
2. It is known that α, β and γ are rational numbers and α + β + γ = 0, then α & sup2; + β & sup2; + γ & sup2; - β γ ‐ γ α ‐ α β = ()
3. A math problem, junior high school, urgent solution The green space area of a city in 2010 is 60 hectares. In order to meet the needs of urban development, it is planned to reach 72.6 hectares by the end of 2012? A simple process description is required
4. Please help me solve a math problem in junior high school, The teacher wrote three formulas on the blackboard: the square of 5-3 = 8 * 2; the square of 9-7 = 8 * 4; the square of 15-13 = 8 * 7. Wang Hua then wrote two formulas with the same rule: the square of 11-5 = 8 * 12, and the square of 15-7 = 8 * 22. Q: let m and n be integers. Please use the formula containing m and N to reflect the above rule
5. I have a math problem that I can't understand all the time One day, three people went to play. They stayed in a hotel. The boss said that it would cost 30 yuan to stay in the hotel. As a result, everyone was given 10 yuan. After they left, the boss forgot that there was a discount in the activity Hotel today, so he asked the waiter to get 5 yuan back to them. On the way back, the waiter secretly hid two yuan. One for each of them, that is to say, one for each of them, It's that everyone paid 9 yuan, 3-9 27 plus the waiter's 2 yuan, but it's only 29 yuan
6. A factory produces a and B products, in which workshop a only produces a product and workshop B only produces B product. The quantity of a product produced by workshop a is 3 pieces less than that produced by workshop B, and the quantity of B product produced by workshop B in 2 days is 1 piece less than that produced by workshop a in 3 days? How many pieces of product B are produced in workshop B every day? (2) The factory price of class a products is 160 yuan per piece, and that of class B products is 210 yuan per piece. A customer needs to buy 100 pieces of class A and class B products at one time. Workshop a and workshop B of the factory produce them for 7 days at the same time when there is no inventory. The cost of purchasing class A and class B products at the factory price is not less than 18500 yuan but less than 18650 yuan Design purchase plan for the customer through calculation
7. 1. Solve the equation: 12-2x + xcos α = 0 24cos α - 2xcos α + X (COS ^ 2 α - Sin ^ 2 a) = 0, please explain in detail 2. Solve the equation: B + 2C + λ BC = 0 a+2c+ λac=0 2A + 2B + λ AB = 0, please explain in detail 3. Find a point on the plane xoy so that the sum of the squares of the distances to the three straight lines X = 0, y = 0 and X + 2y-16 = 0 is the minimum Let the point be (x, y), then the distance from the point to the three straight lines is: | x |, | y |, | x + 2y-16 | / √ 5 I want to know how this √ 5 is worked out?
8. 1. A cylindrical bucket without a cover, measured from the inside, has a bottom diameter of 4 decimeters and a height of 6 decimeters. How many square decimeters of iron sheet is needed to make this bucket? The water depth of the bucket is 5 decimeters, and how many kilograms of water are in the bucket? (take 3.14, 1 liter of water weighs 1 kilogram) 2. The distance between a and B is 264 km. A travels 80 km per hour from a to B by bus. B travels 32 km per hour from B to a by motorcycle. When a runs 200 km, he meets B and asks when a starts ahead of B 3. An electronic dictionary is sold in a stationery shop, and the profit is 15 yuan for each one sold. In order to recover the funds as soon as possible, the price of each dictionary is reduced by 3 yuan. When all the dictionaries are sold out, the profit is 864 yuan. How many electronic dictionaries are sold in the stationery shop? I appreciate the disrespect
9. At present, 1000 balls are packed into 100 boxes, and the sum of balls in any 10 boxes can not exceed 190, then a box can have at most balls () A. 108 B. 109 C. 118 D. 119
10. 1. If {an} is an arithmetic sequence, A3 + a7-a10 = 8, a11-a4 = 4, what is the sum of the first 13 items of the sequence? 2. A has several books, B borrows half and adds one, C borrows half and adds two, D borrows half and adds three, and finally a has two books left. How many books does a have 3. There are two holes a and B on a drum with a volume of 64. Water flows in from hole a and flows out from hole B. if the flow rate through hole a is 3 L / h, what is the flow rate in hole B to ensure that the container can be filled in 96 hours? 4.y=nx／x-n ＝(n×n／x-n)+n
11. 1) (- 4 / 13) + (- 4 / 17) + 4 / 13 + (- 13 / 17) (2) (- 2) × 5 / 4 × (- 9 / 10) × (- 2 / 3) (3) - 2 / 7 - (- 1 / 2) + / - 1 / 12/ (4) / - 16 / × (- 3 / 4-1 / 2 + 3 / 8)
12. 1. First simplify, then evaluate [(3x + 4Y) ^ 2 - 3x (3x + 4Y)] / (- 6y), where x = - 1, y = 3
13. Help me with a math problem, 200 kilograms of oranges and apples are sold as a fruit platter at 2.7 yuan per kilogram. It is known that the weight ratio of oranges and apples is 3:2, and the unit price ratio is 5:6. What is the unit price of oranges and apples?
14. solve equations: x-（2/7）x=(1/14) For a batch of candy, 2 / 5 of the total candy has been packed. For another 21 kg, 3 / 4 of the total candy has been packed. How many kg are there in total? 2. The graduating class charges for photography. The number of students who have not paid is 1 / 7 of those who have already paid. Later, there are 2 people who have paid. At this time, the number of students who have not paid is 1 / 11 of those who have already paid. How many students are there in this class? Note that there must be a process!
15. The scoring rules of football match are: 3 points for winning one game, 1 point for drawing one game, 0 point for losing one game, 13 games in one game ① The team won X Games, lost four and tied_____ Field ② Win x field, product____ Minutes, minus four fields, product____ Points, even_____ Field, product_____ Points ③ If the team wants to score 19 points in all the games, it should win_____ Field
16. 1. Given that the square of a times the square of B plus the square of a plus the square of B plus 1 equals 4AB, find the value of ab 2. If the square of x plus the square of y plus 5 / 4 equals 2x plus y, find the value of (x + y) times XY
17. 1. A bookshelf has two layers. If 60 books are borrowed from the upper layer, the books on the upper layer are 20% more than those on the lower layer. It is known that there are 240 original books on the upper layer, but how many books are there on the lower layer? 2. The perimeter of a round desktop is 4.71 meters. A glass plate of the same size as the desktop should be placed on the desktop. What's the area of this glass plate? (the number should be kept to one decimal place)
18. We know that the ages of two children are respectively x years and y years, and the square of X + xy = 99 2. Someone wants to run a pig farm, which is divided into two square pig farms, the Jianzi pig farm and the piglet farm. It is known that the area of the Jianzi pig farm is 40 square meters larger than that of the piglet farm, and the total length of the wall of the two pig farms is 80 m, so the area of the piglet farm is calculated (there is no public wall in the two farms)
19. 1. Square of X (A-1) + 4 (1-A) 2. (one square of 1-2) x (one square of 1-3) x.x (one square of 1-9) x (one square of 1-10) All the above questions are factorized. The first question is only factorized, and the second one is factorized,
20. A piece of paper with a thickness of 0.1 mm is folded in half for 5 times. What is its thickness at this time? Assuming that continuous folding is always possible, then how many times after folding. The thickness can exceed your height? Please see clearly It is assumed that continuous folding is always possible It's a hypothesis. And please make a formula, 65 meters