Mathematics application problems for the first year of junior high school. There is only 1 course. T

Set: purchase A x unit, purchase B y unit, purchase C z unit.

Option 1: Purchase A and B, with x+y=50, 1500x+2100y=90000

The solution yields x=25, y=25;

Scheme 2: Purchase A and C, with x+z=50, 1500x+2500z=90000

The solution is x=35, z=15;

Plan 3: Purchase B and C, with y+z=50, 2100y+2500z=90000

The solution is y=, z=. (does not fit the topic, discard).

Answer: There are two schemes, the first one: purchase 25 units of A and 25 units of B. The second type: purchase 35 units of A and 15 units of C.

Let A: X B: Y C: Z

Option 1: Purchase A and B, with x+y=50, 1500x+2100y=90000

The solution yields x=25, y=25;

Scheme 2: Purchase A and C, with x+z=50, 1500x+2500z=90000

The solution is x=35, z=15;

Plan 3: Purchase B and C, with y+z=50, 2100y+2500z=90000

The solution is y=, z=. (does not fit the topic, discard).

The profit in question 2 can be calculated based on the above two scenarios.

Solution: Let A be x and B be (50-x).

1500x+(50-x)2100=90000 gives x=25

So both A and B are 25

The above is one of a kind. It can also be A-C, B-C. The same method is calculated, and the result is an integer.

1500x+2100(50-x)=90000 No solution.

1500x+2500(50-x)=90000x=25 A 25 pieces C 25 pieces.

2100x+2500(50-x)=90000 solution is a fraction and is not eligible.

Design: bolt workers x people.

From the meaning of the title, it can be seen that 12x=[18*(28-x)] 2[504-18x] 2=12x

252-9x=12x

21x=252

x = 12 bolt workers have 12 people.

Nut worker: 28-12 = 16 (people).

ps.Checked and correct].

I don't use the method of solving equations, but I do the math

If two nuts are treated as one nut, a person can only produce 9 nuts a day, because two females are against one bolt.

So the number of people who produce nuts The number of people who produce bolts = 12 9 = 4 If 34 people produce nuts, 3 people will produce bolts.

That's a group of 7 people.

28 people can be divided into 4 groups.

So the number of people who produce nuts is 4*4=16

The number of people who produce bolts is 3*4=12

Solution: Set x workers to produce nuts.

2*12x=18(28-x)

x=12A: 12 workers produce nuts.

Hope it helps!

Using the binary system of equations, let the number of people producing bolts be x and the number of nuts produced is y, then there is 2*12x=18y (the meaning of one bolt with two nuts); Due to the number of people, there is x+y=28 by.

2*12x=18y

x+y=28

The solution yields x=12, y=16

That is, 12 people should be allowed to produce bolts and 16 people to produce nuts.

Can you read it?

Set the bolt worker x and the nut worker 28-x

12x=18*2*（28-x）

48x=1008

x=21

Set up the production of bolts x people, the production of nuts y people.

x+y=28

12x=9y one bolt with two nuts, so, to produce 18y nuts, 9y is the total number of bolts.

The solution yields x=12, y=16

A: There are 12 people in the production of bolts and 16 people in the production of nuts.

Hello: It is our pleasure to solve the problem, we will try our best to solve your problem, unfortunately I will not.

If x people produce bolts, then the production of nuts has 28-x 12x*2=(28-x)*18 x = 12 of the solution equation A: 12 people produce bolts and 16 people produce nuts.

12 people produce bolts and 16 people nuts.

The product can be discounted at a minimum.

3000x=2000×(1+5℅)

3000x=2000+100

3000x=2100

x=2100÷3000

x = equivalent to 7% off.

This item can be discounted at a minimum of 7%.

Set the price to be $x.

x-2000) 2000 is greater than solution x=2100

2100 3000= Minimum 7% off.

You can first set it to be sold at x discount, so that you can list the formula, selling price = selling price.

200（1+5%）=300x

Will you solve this equation?

If it is sold at x discount, the selling price can be expressed as 300x 10 yuan, and the equation can be obtained.

300x/10=200（1+5%）

Get x=7

Set the price of this product after the discount is X yuan, which is sold at a Y discount, so according to the title:

x-200）/200*100%=5%

Get x=210 (yuan).

y=210/300=

A: This item is sold at 7% off.

Solution: The profit margin is 5%.

The actual sales price is 200 (1+5%) = 210 (yuan) 210 300 = 7 10

Seven percent off. A: This item is sold at 7% off.