A construction site needs 44 tons of cement, which has been transported 5 times by a 4-ton truck. The rest is transported by a 2.5-ton truck, and can it be transported 10 times?

A construction site needs 44 tons of cement, which has been transported 5 times by a 4-ton truck. The rest is transported by a 2.5-ton truck, and can it be transported 10 times?

(44-4 × 5) △ 2.5, = (44-20) △ 2.5, = 24 △ 2.5, = 9.6, ≈ 10 (Times); it can be seen that 10 times can be completed; answer: another 10 times can be completed
The transport team needs to transport 88 tons of cement. First, it uses 7 vehicles with a load of 4 tons to transport the cement once, and the rest uses vehicles with a load of 5 tons to transport the cement at one time. How many vehicles are needed?
We need the equivalent relation
88-（7*4）=60
60/5=12
12
19............
Need 12 5 ton vehicles to transport!
A truck and a car start from city a to city B at the same time. The truck runs 75 kilometers per hour and the car 80 kilometers per hour. The distance between the two cars is 15 kilometers after a few hours?
80-75 = 5 km
15 △ 5 = 3 hours
There are two granaries, one is 20 tons of grain and the other is 15.6 tons. After the second warehouse gives part of the grain to the first warehouse, the grain in the first warehouse is exactly the same as that in the second warehouse
How many tons of grain did warehouse B deliver to warehouse a?
Your question has taken out the most important several times
1. Xiaoli, Xiaoqiang and Xiaohong went to the supermarket to participate in social practice activities and fruit sales. It is known that the purchase price of the fruit is 8 yuan / kg. The dialogue is as follows:
Xiao Li: if you sell it at 10 yuan / kg, you can sell 300 kg per day
Xiaoqiang: if you sell it at 13 yuan / kg, you can make a profit of 750 yuan per day
According to the unit price relationship between X and y, we can find the unit price relationship between X and Y three times a day
2. A travel agency has put forward a preferential scheme. From now on, the price y of each line per person is a function of the original price X. now we know that the price of the original line is 2100 yuan and 2800 yuan, and the current travel price is 1800 yuan and 2300 yuan. We can find the functional relationship between Y and X (without the value range of x)
1. It is known that the daily sales volume is y and the unit price is X
Since there is a linear function between the daily sales volume y and the unit price x, let y = KX + B, then the profit is (X-8) * y = (X-8) * (KX + b)
also
If it is sold at 10 yuan / kg, 300kg can be sold every day, that is, when x = 10, y = 300, that is, 10K + B = 300
When x = 13, (X-8) * (KX + b) = 750, that is, (13-8) * (13K + b) = 750,
Combining the above two equations: k = - 50, B = 800
Substituting k = - 50, B = 800 into y = KX + B, y = - 50x + 800 (x > 0)
2. The price per person of each line y is a function of the original price per person X
Let this function be y = KX + B
When the original price x = 1800, the corresponding current price y = 2100
When the original price x = 2300, the corresponding current price y = 2800
Substituting (18002100), (23002800) into the equation: y = KX + B
The simultaneous solution is: k = 1.4, B = - 420
The functional relationship between Y and X is y = 1.4x-420
1.y=300，x=10
y=750/(13-8)=150,x=13
Let y = KX + B
Substituting two points into k = - 50, B = 800
y=-50x+800
2. x=1800,y=2100
x=2300,7=2800
Let y = KX + B
Two point substitution, k = 1.4, B = - 420
y=1.4x-420
1、X Y
10 300
13 750／（13-8）=150
In this way, two points (10300) and (13150) are obtained. Let the analytic expression of the function be y = KX + B
Take the point in and you get a straight line y = 800-50x.
2. In the same way, if you know two points, just bring them to the equation and calculate them
Y=5/7X+300
1: Let y = ax + B. When the unit price is 13 yuan, the sales volume is 750 / (13-8) = 150
So there are: 300 = 10A + B, 150 = 13A + B
The solution is a = - 50, B = 800. So y = - 50x + 800
2: It's actually similar to the first question. Let y = ax + B
The equation: 1800 = 2100A + B, 2300 = 2800a + B
The results show that a = 5 / 7, B = 300
So it is: y = 5x / 7 + 300
1. Let y = KX + B, when the selling price is 13 yuan / kg,
Sales volume y = 750 / (13-8) = 150,
Then there are the equations 10K + B = 300,13k + B = 150,
The solution is k = - 50, B = 800;
2. Let y = KX + B,
There are equations 2100K + B = 18002800k + B = 2300,
The solution is k = 7 / 300
The first is: y = 800-50x, the second is y = 5 / 7X 3 = y, ask the teacher about the specific process
Xiao Ming read a story book. On the first day, he read 24 pages, accounting for one fifth of the whole book. On the second day, he read 3 / 8 of the whole book. How much is left?
Because 24 pages account for one fifth of the whole book, the total number of 24 divided by 1 / 5 = 120 pages
The next day I read 120 * 3 / 8 = 45 (Ye)
120-24-45 = 51 Pages left
It takes 8 hours for a truck to arrive at city B, and 10 hours for a bus to arrive at city a from city B. after 4 hours, the distance between the two vehicles is still a few percent of the whole journey
Thinking of solving problems
1-1/8x4-1/10x4
=1-1/2-2/5
=1/10
1-4×1/8-4×1/10=1/10
A: it's still one tenth of the distance
A walks 1 / 8 an hour, B walks 1 / 10 an hour
1/2-2/5=1/10
1/10
Distance: 1-4x (1 / 8 + 1 / 10) = 1 / 10
If the total distance is x, then the speed of freight cars is x / 8 and that of passenger cars is x / 10
Four hours is 4x / 8 + 4x / 10 = 9x / 10, so the distance between the two cars is 1 / 10 of the whole journey
There are two granaries A and B. The tons of grain stored in the warehouse A are 5 / 7 of that in the warehouse B. if the tons of grain stored in the warehouse B are 6 tons, the tons of grain stored in the warehouse A are the same as those in the warehouse B
There are two granaries A and B. in the past, the ton of grain stored in warehouse A is 5 / 7 of that in warehouse B. if the ratio of the ton of grain stored in warehouse B to that in warehouse A is 4:5, how much is each of warehouse A and warehouse B?
Answer 5 + 7 = 12 4 + 5 = 9 6 / (7 / 12-5 / 9) = 216 tons B 216 / (1 + 5 / 7) = 126 tons a 216-126 = 90 tons
Help solve a math problem of grade two in junior high school! Thank you~~~
A city adjusts the water price. If the water consumption is less than 7 cubic meters, it will charge 1 yuan per cubic meter plus 0.2 yuan of sewage treatment fee. If the water consumption is more than 7 cubic meters, it will charge 1.5 yuan per cubic meter plus 0.4 yuan of sewage treatment fee. Suppose the water consumption is x cubic meters and the water fee is y
1. Write the water charge equation for less than 7 cubic meters and the equation for more than 7 cubic meters
2. There are 50 families in a courtyard, the total water cost is 541.6 yuan, and the water consumption of each family is not more than 10 cubic meters
⑴y=1.20x [0≤x≤7]；
Y = 1.20x + 1.90 (X-7) [x > 7]
(2) if each of the 50 households uses 7 tons, the total water fee will be paid:
420 × 50 = 1.7 yuan
The actual payment is 541.6 yuan, and the excess 541.6-420 = 121.6 yuan, that is, the excess water 121.6 △ 1.9 = 64 tons,
Suppose that the super water users all use 10 tons, that is, super 10-7 = 3 tons
Super water users 64 △ 3 = 22
Therefore, there may be at most 50-22 = 28 users with water consumption less than 7 tons this month
Note: if each household uses 7 tons, the excess water consumption is the minimum; if each household uses 3 tons of excess water, the excess water consumption is the least. Therefore, the number of users who do not use excess water is the most
I read a 180 page story book. I read 1 / 6 on the first day and 2 / 9 on the second day. How many fewer pages did I read on the first day than on the second day?
180*2/9-180/6=10