Two questions at the beginning of the first year, one yuan at a time. Thanks 20

1.Set up to meet after x hours.

According to the title: 50x+75(x-1)=275

x = hours. 2.The cost of armor clothing is xThe cost of B clothing is (500-x).

Analysis: A sells price, A makes a profit.

According to the title: ( =157

x=300A cost: 300 yuan; B cost: 200 yuan.

1.Solution: Let's meet after X hours.

According to the title: 50x+75(x-1)=275

50x+75x—75=275

125x=275+75

x=2.Solution: The cost of armor is xThe cost of B clothing is (500-x).

Analysis: A sells price, A makes a profit.

x=300A cost: 300 yuan; B cost: 200 yuan.

Set the jasmine pot bought by Xiao Ming x pot, and the moon flower is y pot, then.

4x+3y=27

Discuss on a case-by-case basis.

When x=0, y=9, this situation can mean that Xiao Ming did not buy jasmine, but bought nine pots of moon flowers.

When x=1 y=23 3, it is not an integer, and this is not true.

When x=2, y=19 3 does not hold.

When x=3, y=5, that is, Xiao Ming bought 3 pots of jasmine and 5 pots of Yueji.

When x=4, y=11 3 is not true.

When x=5, y=7 3 is not true.

When x=6, y=1, that is, Xiao Ming bought 6 pots of jasmine and 1 pot of Yueji.

According to the column: 4x+3y=27

Solve the values of x and y in the equation with x=0 and y=9

Let y=0, x=, because it is not an integer, so make adjustments.

Let y=1 and x=6, so it is optimal to buy 6 boxes of jasmine and 1 box of moons.

5th grade of elementary school, right? This one is going to be listed!

Discuss When. Jasmine 1 pot ...

Jasmine 2 pots ...

Jasmine in 3 pots.

Jasmine 6 pots ...

I'm sure you will!

The area that needs to be painted in each room is x m2

8*x-50) 3=(10*x+40) 5 solution gives x=37

The area that needs to be painted in each room is 37 m2

The elements you give to solve the problem are not enough, and the efficiency of brushing the wall of the first-level technician and the second-level technician is not given, how to solve the problem?

Solution: Suppose a mechanic paints the wall for x a day, and the area that needs to be painted in each room is y.

Then: 3x=8y-50

5x=10y+40

Solution: x=82

y=37A: The area that needs to be painted in each room is 37m2

Average second condition: each person can brush 2 rooms and 8 square meters.

Then he substituted the first condition: 3 people can brush 6 rooms and 24 square meters.

The remaining 50 square meters is the area of the two rooms after removing 24 square meters.

Then the two rooms are 50 + 24 = 74 (square meters).

74 divided by 2 is 37, which is the area that needs to be painted in each room.

Formula: 10 5 = 2 (pieces) 40 5 = 8 (square meters) 3 * 2 = 6 (pieces) 8-6 = 2 (pieces).

50 + 24 = 74 (square meters) 74 2 = 37 (square meters) Answer: The area that needs to be painted in each room is 37 square meters.

1.Xiaoli buys apples and oranges, 4 kilograms of apples and 2 kilograms of oranges, which costs 18 yuan; If it costs yuan to buy 2 kilograms of apples and 4 kilograms of oranges, find how many yuan per kilogram of apples and how many yuan per kilogram of oranges.

Apple X, Orange Y

4x+2y=18 8x+4y=36

2x+4y=

Subtract to get: 6x=

x= and substitution: y=

2.A and B two granaries, A transports 14t of grain, B transports 10t of grain, and the number of the two granaries is equal; After A transports 8t and B transports 18t, B is 6 times that of A. Ask A, how many granaries were in each of B's granaries?

A x, B yx + 14t = y-10t y - x = 24 t6 (x - 8t) = y + 18t

6x-48t=y+18t 6x-y=66t: 5x=90t

x=18t: y=42t

The coins of 1 jiao and 5 jiao are 5 yuan and 3 jiao, of which the coins of 1 jiao and 5 jiao are 1 jiao x and 5 jiao y

x+y=21

x+5y=53

Subtract to get: 4y=32

y=8 substitution: x=13

4.There are the following activities to buy books, buy 1-19 copies, each book can be 9% off; More than 20 copies (including 20 copies), 7% off each book, 5 yuan per book. At present, people buy books twice, a total of 30 books, and spend a total of 129 yuan, asking how many books to buy twice.

The first x, the second y

x+y=30 9x+9y=2709x+7y=258

Subtract to obtain: 2y=12

y=6 substitution: x=24

The binary equation also asks what to set and what to solve, according to the book.

Ask anything, your brain will rust!!

Just eliminate an unknown first.

Set up the fast car to drive and dismantle the quarrel out that the two cars met when X was an hour.

75+50）x=275-50*1

Encounter distance = speed and * meeting time, because it is 1 hour after the slow train starts, the fast train starts to drive, and the encounter distance = the distance of the whole process - 1 hour of the slow train).

125x=225

x = hours) Answer: The slow train meets the fast train after the hour of driving.

If the cost of clothing A is $x, the cost of clothing B is $500-x.

x*(1+50%)*

x*x=300500-300=200 yuan.

Answer: If the cost of clothing A is 300 yuan, the cost of clothing B is 200 yuan.

1.Let the total distance between AB be 1Let Xiao Ming's speed be x meters per minute, and Wang Yun's speed will be y meters per minute. then the time is 1 x and 1 y minutes.

80x+80y=1(1), 100x+40y=1 (2) The two formulas together get 80x+80y=100x+40y, subtract to get 40y=20x and then x=2y(3) and then substitute (1) or (2) to get 240y=1, that is, 1 y=240, 1 x=120 So, it takes 2 hours for Xiao Ming to finish. Wang Yun takes 4 hours.

2.I think there's a problem. The tiger walks 3 meters in one step. Then he walked 102 meters when he crossed the 100 line, then walked 98 meters on the return trip or walked 102 meters back to the starting point??

x=60*80/40

y=40x/(60+40-80)

x=120y=240

The result of this game is that the Lions won.

The lion has no waste.

x=60*80/40

y=40x/(60+40-80)

x=120y=240

The result of this game is that the Lions won.

First of all, according to the known conditions, the monthly electricity consumption of 460 degrees can be executed

1）x+y=460

Because the electricity in May is more than in April, then the electricity in April is less than 460 2=230, and the excess in May is 230, first set Y is not greater than 400, and then the equation can be listed:

2）（y-230）*

Find y=280 and x=180

Let y be greater than 400, then equation (2) is:

y-230）*

Find y=x= two answers.

The Handsome Wolf Hunting team will answer for you:

Zhang Qi's fellow scholar shared 460 kWh of electricity this year, and the electricity consumption in May was more than that in April, so the electricity bill in April was billed by yuan, and the electricity bill in May was billed by (yuan), (because (400-230) > yuan, the electricity consumption in May did not exceed 400 kWh.) )x+y=460

Solution: x=180, y=280, so the monthly electricity consumption is 180 kWh and 280 kWh respectively.

According to the title, it can be seen that the monthly electricity consumption is 460 kWh, the electricity consumption in May is more than that in April, and the electricity consumption in April must not exceed 230, and the electricity bill should be;The electricity bill for May is, or is;

Column equation: 1) x+y=460

2）x+y=460

Solution (1): x=180 y=280

2): x is a negative number and is not true.

So the electricity consumption in April is 180 kWh, and the electricity consumption in May is 280 kWh.

The first question lacks the total amount of work and cannot be answered.

Question 2: After x minutes, plug the bottom plug of the closed inspection.

From the inscription, it can be seen that the water injection pipe is filled with water 1 5 per minute, and the water outlet pipe is 1 101 5-1 10) x + 1 5 x = 1 per minute

x=10 state bi 3

It took a total of 20 3 minutes to fill the tank.

Let A need to complete this project alone needs to cost x million yuan per day, B alone needs to complete this project needs to cost y million yuan per day, A and B two teams need to cooperate with 1 (1 30 + 1 120) = 24 days to complete, the equation 24 (x + y) = 120, A does it alone for 20 days, and B needs to do (1-20 30) (1 120) = 40 days to complete, the equation 20 x + 40 y = 110 is obtained, and the solution is x = , y = , so A takes 30 days to complete this project alone It takes 30 days to complete the project needs to cost 30 x =1.35 million yuan, B takes 120 days to complete the project alone, and the cost is 120y = 600,000 yuan.

Suppose A needs x million per day, and B needs y million per day, then.

20*x+[(30-20)*(120 30)]*y=1101 (1 30+1 120)*(x+y)=120 to solve this binary equation.

x = 10,000 y = 10,000.

Then, A needs x * 30 = 1.35 million to complete alone.

B needs to be completed separately y*120=600,000.

Solution: (1-1 30 20) 1 120 = 40 days 1 (1 30 + 1 120) = 5 120

120 5 120 = 50,000 yuan.

Set A to be $10,000 per day and B $10,000 per day.

20x+40y=110

x+y=5 solution: x=

y = 10,000 yuan, 10,000 yuan.

A: Team A will need 1.35 million yuan to complete this project alone.

Team B completed the project alone, each costing 600,000 yuan.

It costs 1.35 million yuan for A to complete it alone, and 600,000 yuan for B to complete it alone.

Let's let A do a separate system of x10,000 yuan and B y0,000 yuan as a system of binary equations: 4 5x +1 5y=120 2 3x+1 3y=110 Result x=135 y=60

A = A day of engineering B = B day of engineering.

a+b)*24=20a+40b

24a+24b=20a+40b

4a=16b

a=4ba+b)*24=5b*24=120b: number of days required by B = 120b b=120 number of days required by A=120b 4b=30

A = Fee for Day A B = Fee for Day B.

a+b)*24=120 a=5-b

20a+40b=110 100-20b+40b=110 b= a=

The total cost of B = the cost of A =