Column algebra

1.a gram of water is mixed with b gram of salt to form brine, and the percentage of salt in the brine is

2. If the price of a commodity is one yuan after x% reduction, then the original price of the commodity is Yuan Yuan.

3. There is a job that Party A needs a day to complete alone, and Party B needs b days to complete alone. If Party A and Party B cooperate to complete this work, how many days will it take to complete this work?

4. In order to encourage electricity conservation in a certain place, the charging standards for users' electricity consumption are as follows: if the monthly electricity consumption of each household does not exceed 100 kWh, it will be charged at one yuan per kWh; If it exceeds 100 degrees, the excess will be charged twice per degree. A household uses electricity 180 kwh a month, and has to pay RMB this month.

Only equations (groups) are incomprehensible.

1.Students from Class A and Class B take part in afforestation. It is known that Class A plants 5 more trees every day than Class B. The number of days for Class A to plant 80 trees is equal to the number of days for Class B to plant 70 trees. If Class A plants X trees every day, the equation is as follows

2. Someone deposits 2,000 yuan in the bank for one year, takes out 1000 yuan for shopping after the expiration, and deposits the remaining 1000 yuan and the interest due in the bank for one year. If the deposit interest remains unchanged, the principal and interest after maturity will be *** 1320 yuan. If the annual interest rate of this deposit method is x, the equation is obtained.

3. There is a conference room with a length of 20m and a width of15m. There is a carpet in the middle of the conference room, and the area of the carpet is half that of the conference room. If the width of the blank area around the carpet is x meters, the equation listed is

A factory plans to produce 65,438+0,000 machine tools in X days. Later, in actual production, it produced 25 more machines every day than originally planned, and the result was completed two days ahead of schedule, so there was an equation.

A and B are 60 kilometers apart, and two people ride bicycles from A and B respectively. If A leaves 30 minutes earlier than B, and A travels 2 kilometers less per hour than B, then the distance they travel when they meet is exactly the same. If the circulation speed of a is x kilometers per hour, the equation is obtained.

Column inequality

A bicycle factory produces and sells a new type of bicycle this year, and now we provide you with the following information:

Last year, the factory prepared 1000 wheels of this bicycle. This year, the wheel workshop can produce 1500 wheels per month on average, and each bicycle needs two wheels.

(2) The assembly workshop of our factory (the production workshop of the last process of bicycles) can assemble at least 1 1,000 bicycles per month, but not more than 1 1,200 bicycles;

(3) This year, the factory has received orders for bicycles from customers all over the world *** 14500;

(4) The ex-factory sales unit price of this bicycle is 500 yuan/vehicle.

The sales of this kind of bicycle in this factory this year is one million yuan. Please judge the range of A according to the above information.

Solving application problems with column equations;

1. The original price of a commodity in 50 yuan was reduced in June 5438+00 due to poor sales 10%, and the price was increased from June 5438+0 10, and the price in February/6 was 64.8 yuan.

Q: (1) What is the price of this commodity in June?

1 1 and 65438+what is the average price increase in February?

Team a and team b each transport 150 tons of goods. It is known that Team A has five more cars than Team B, while Team B has an average of more cars 1 ton of goods than Team A. Both teams have finished loading at one time. How many cars are there in Team A and Team B?

Two people, Party A and Party B, can complete a task in six days. It takes 9 days for Party A to complete it alone, and how many days does it take for Party B to complete it alone?

The distance between a and b is 30 kilometers. A walks more per hour than B 1 km, and the time from A to B is less than B 1 hour. How many kilometers do A and B walk per hour?

Teachers and students of a school visited a place 28 kilometers away from the school and began to walk at a speed of 4 kilometers per hour. The rest of the journey is by car at 36 kilometers per hour, the whole journey 1 hour. How long does it take to walk?

The following are difficult application problems:

1. Two trains run on two parallel tracks respectively, in which the express train is 100 meters long and the local train is 150 meters long. When two trains are driving in opposite directions, it takes 5 seconds for the express train to pass through a window of the local train (from the time when the front of the express train arrives at the window to the time when the rear of the express train leaves).

(1) Find the sum of the speeds of the two trains, and the time it takes for the local train to pass through a window of the express train when the two trains are driving in opposite directions (from the time when the local train head arrives at the window to the time when the local train tail leaves);

If the two cars are driving in the same direction, and the local speed is not less than 8m/s, how many seconds does it take for the express train to catch up with the local train from the back to leave the local train?

2. A project is completed by two teams of Party A and Party B within 6 days. The manufacturer needs to pay Party A and Party B * * 8700 yuan, and Party B and Party C will work together 10 day. The manufacturer needs to pay Party B and Party C 9500 yuan, and Party A and Party C will work together for 5 days to complete 2/3 of the whole project. The manufacturer needs to pay Party A and Party C..