Kneel for an application problem 25, kneel for an application problem

108 (person) ....Find the total number of students in two classes.

108*5 12 45 (person) ....The number of people in class A is 108*7 12 63 (people) ......Finding the number of people in class B regards the total number of people in the two classes as the unit "1", class B accounts for 7 12 of the total number of the two classes, that is, 7 (5+7), class A accounts for 5 12 of the total number of the two classes, and after class B transfers 3 people to A, class B accounts for 5 9 of the total number of students in the two classes, and class A accounts for 4 9 of the total number of the two classes(This is where the knowledge of the application of ratios, which I am a sixth-grade math teacher and teaches students to analyze in this way.) To learn mathematics well, you must integrate all aspects of knowledge).

The purpose of this is because the total number of students in the two classes remains the same.

A: Originally, there were 45 people in Class A and 63 people in Class B.

There were two classes of A and B, and there were originally x and y people.

x=5/7y

x+3)=4/5(y-3)

x=45y=63

If there are x people in class B, then there are 5 7x people in class A, and the equation is:

5/7x+3=4/5*（x-3）

x=63，5/7x=45

A: There were 45 students in Class A and 63 students in Class B.

Solution: If there were x people in class B, then there were (5 7) x people in class A.

5/7)x+3=(4/5)(x-3)

1。If there are 2x technicians, then the average employee is x.

Solve the equation: 2x+x=15

Score: x = 5 technicians 10 people, ordinary employees are 5 people.

2。Assuming A and B are the same, then 15A = 9000 and A = B = 600 yuan.

If a>b>300 and both a and b are integer multiples of 100, then only a=700 and b=400 can be issued.

Turnover in the middle of the year = 10,000 yuan.

Turnover in the second half of the year = divided by 7 9 = 2433.5 million yuan.

Solution: Assuming that the original plan to complete this project takes x months, and the original work efficiency is y, then the workload of this project is xy

The actual working time is (x-3) months, the actual work efficiency is y(1+12)=xy=, when solving the equation, both sides of the equation are divided by y at the same time, and the following is obtained

x=x=x=28

The project was originally planned to be completed in 28 months.

It was originally planned to take x months to complete the project.

x = (x-3)*(1+12%)

x= 28

……Set the original plan for x months.

1 x)*(1+12%)=1 (x-3) gives x=28

In fact, it is to use efficiency to do the actual unknown quantity, because the improvement is efficiency, so it cannot be directly calculated with the improvement of time and efficiency, so the efficiency is expressed by time.

There are several to the bottom layer: 15.

The total height of this pile of steel pipes is: 150cm

If they don't rest, they can produce 14 * (4 + 3) = 98 in so much time, and the actual production is 77, a difference of 21, if you want to work together as little time as possible, you have to do a slow break, A is slower, let him rest longer than B rest.

21 3=7.

Solution: Let the two machines A and B work together for x hours, and machine B works separately for Y hours.

3＋4）x＋4y＝77………

x＋y＝14………

Solution: x 7

Y 7So, two machines, A and B, worked together for 7 hours.

First of all, let the minimum be x hours, because it is the least, so let b produce (14-x)*4+7x=77 when a single machine

56+3x=77

3x=21x=7

xy=x= This is an indefinite equation Lukai.

If y=1 x=

y=2 x=

If it is a unary equation, it lacks the conditions of accompanying Chang and cannot be used as a quick wheel.

Because the stationery store makes as much profit as selling the same number of 8 yuan per commemorative book, it is necessary to calculate how much profit it makes by selling the 8 yuan commemorative book. Then, on the basis of calculating the purchase price of 12 yuan for the commemorative book, plus the amount of money that was profitable, it is the current selling price of each copy.

8*(1-70%)=......The purchase price is 70% of the list price, then 30% is the amount of profit.

12*70%+......The price is 12 yuan, and the current price is 108 copies.

Xiao Ming bought 10 commemorative books.

Xiao Ming bought a total of x commemorative albums, the original price of 8 yuan commemorative albums is 8x70%=, and the profit of each book is yuan; The original price of the 12 yuan commemorative book is 12x70%=, and the profit per copy is yuan.

x=10 Xiao Ming bought a total of 10 commemorative albums.

The purchase price of each 8 yuan book is yuan, and the yuan is earned; The purchase price of 12 yuan is yuan, and it is normal to earn yuan.

Set up x volumes. If it is a book of 8 yuan, the store earns: yuan. Now buy 12 yuan booklet x copies, and the money earned by the store is:

x=10 (book) Xiao Ming bought a total of 10 commemorative albums of 120 yuan