Seven mathematical application problems
1. Grade 7 students from a middle school in Shanghang County go out for social practice. If there are 45 people in each car, 15 students don't have a car. If there are 60 people in each car, then one car can be vacated. Q * * * How many cars and students are there?
7. A middle school organizes students to have a spring outing. It was originally planned to rent a number of 45-seat buses, but 15 people had no seats. If you rent the same amount of 60 pounds
There is another car, and the others are just full. It is understood that the daily rent of 45 buses is 220 yuan, and the daily rent of 60 buses is 300 yuan.
(1) How many students are there in the spring outing? How many 45-seat buses were originally planned to rent?
(2) If you rent a similar car and want everyone to have a seat, how to rent a car is more cost-effective?
8. Class A and Class B of Grade 9 of Guangming Middle School donated money for Project Hope. The total donations of the two classes are the same, both higher than 300 yuan and lower than 400 yuan. It is known that one person in Class A donated 6 yuan and the rest donated 9 yuan. One person in Class B donated 13 yuan, and the rest donated to 8 yuan. What is the total number of students in Class A and Class B?
9. (Harbin, 2006) Xiaoyue Automobile Sales Company went to an automobile factory to buy A and B? Two types of cars, 10 A, 15 B can be purchased for 3 million yuan, and 8 A and 18 B can also be purchased for 3 million yuan. (65,438+0) How much are the two cars?
(2) The car sales company sells 1 model A car, and it can get 8000 yuan, and the sales amount is 1? A b? A car can make a profit of 5000 yuan, and the car sales company is going to buy 30 A and B cars with no more than 4 million yuan. The total profit after all these two cars are sold is not less than 204,000 yuan. How many kinds of car purchase schemes are there? In these car purchase schemes, how many million yuan did the car sales company earn after selling all these cars?
1 1. In the maintenance project of Wuhan Jianghan No.1 Bridge, it is planned that two engineering teams will jointly complete a project. From the data of the two engineering teams, we can know that if the two engineering teams work together for 24 days, it will be completed; If two teams work together 18 days, then team a works alone 10 days, which just ends. Excuse me:
(1) How many days does it take for Team A and Team B to complete the project alone?
(2) It is known that the daily construction cost of Team A is 6000 yuan, and that of Team B is 3500 yuan. If the total cost of this project does not exceed 220 thousand, how many days will Team B have to work at least?
Teaching plan exercises of the whole class courseware in grade one summarize the historical geography of mathematical English in China.
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answer
1. solution: with x cars and y students, then
45 1560( 1)xyxy？ Solution 5
240xy？
A: There are 5 cars and 240 students. 7. Solution: (1) Students from ***x participated in the spring outing. It was originally planned to rent 45 buses.
According to the question, it means 45 15240
60( 1)5
yx
xyxy
To solve this equation group, A: There are 240 students for a spring outing, and it was originally planned to rent five 45-seat buses.
(2) Rent 45 buses: 240÷45≈5.3, so it is necessary to rent 6 buses, and the rent is 220×6= 1320 yuan; Rent a 60-seat bus: 240÷60=4, then you need to rent 4 buses, and the rent is 300×4= 1200 (yuan). 8. Let the number of class A be X and class B be Y. 。
9 1
69( 1) 138( 1)8
30069( 1)40027
33443
9yxxyxx
That is, because X is an integer, x=34, 35, 36, 37, 38, 39, 40, 4 1, 42, 43, 44.
And because y is also an integer, x must be a multiple of 8, so x=40,? Y=44, so the total number of people is 84. 9. Analysis: Two types of cars, A and B, can be set up, each of which is X million yuan and Y million yuan respectively.
Solve the problem by equations (1). Solution: (1) Suppose that each car of Model A is RMB 10,000, B? The price of each car is ten thousand yuan,
According to the meaning of the question, 10 15300, 15.
8 18300. 10.xyxxyy
Solve.
Answer: A car and B car are 65,438+10,000 yuan and 15 respectively. ten thousand yuan
(2) If you buy a car, you will buy a car of type B (30-a). According to the meaning, you get 15 10 (30) 400, 0.80.5 (30) 20.4.
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Solve this set of inequalities, 18≤a≤20,
∫a is an integer, ∴a= 18,19,20, ∴ There are three car buying schemes. ...
After the car sales company sold all these cars; The profit of scheme 1 is18× 0.8+12× 0.5 = 20.4 (ten thousand yuan); Gain19× 0.8+1× 0.5 =? 20.7 (ten thousand yuan); The income of the third scheme is 20×0.8+ 10×0.5=2 1 (ten thousand yuan). 1 1. (1) solution:? Let A do X days alone and B do Y days alone.
1 1
14024 1 1 1060 18() 1x xyyx？
The solution fits the meaning of the question. (2) Let A be construction and B be construction. 140600.60.3522a
Babu (female name)
,
The solution is that b≥40, that is, B has at least 40 days of construction time.
I hope to adopt these.