Math Masters Help Me!! 100,000 urgent, good chasing points .

1.The number of students in class A and class B is A, the number of students in class A participating in the mathematics group is x, and the number of students in class B without participation is 3x; If the number of participants in the Mathematics group in Class B is Y, the number of students who did not participate in Class A is 4Y. According to the title.

x+4y=a, 3x+y=a, the solution is x=3a 11, y=2a 11, so the number of people who did not participate in class A 4y is the number of people who did not participate in class B 3x 8 9.

2.Let the time x be used to come back, and the speed of coming back is y, then the time to go is y-12, according to the topic.

x+, xy=, solution.

x = 8 hours, y = 36 km hours.

The total round-trip travel is 2xy=576 km.

3.Let the bicycle speed be x and the time of B is y, then there is.

60=3x*(y-4), 60=xy, solution.

x = 10 kmh and 3x = 30 kmh, i.e. 30 kmh and 10 kmh for motorcycles and 10 kmh for bicycles.

1.The number of people who did not participate in class A is x, and the number of people who did not participate in class B is y.

Then the number of participants in class A is 1 3y, and the number of participants in class B is 1 4x, because the number of people in the two classes is equal.

So x+1 3*y=y+1 4*x

Solution x y=8 9

2.Set: a total of 2x kilometers, the time of return t hours, then the time of going x t-x

t+solution x=288 t=8 2x=576

A: The total round trip is 576 kilometers.

3.Let the speed of the bicycle be x, then the speed of the motorcycle is 3x60 x-60 3x=4

The solution is x=10 3x=30

A: The speed of the motorcycle is 30 km/h, and the speed of the bicycle is 10km/h.

The yuan is 1 3 * 1 3 = 1 94 (1 9) = 4 * 9 = 36 yuan of the money that Xiaohong asked for from her mother.

Xiaohong asked her mother for 36 yuan.

2. Earned 7200 * 20% = 1440 yuan.

Loss of 7200 80%-7200 = 1800 yuan 1800 1440

So I lost money selling these two computers.

It's very simple, the first question, she still has 4 yuan left in the end, which is the rest of the drink, that is, the third, and then you can calculate the remaining 12 yuan after buying a gift.

And this is the remaining third of the gift, so it is calculated that a total of 36 yuan is required.

The second question is that a computer earns 20% of 7200, that is, 1440 A computer is sold for 7200 and loses 20%, that is, it only sells 80% of the original price, the original price is 9000, and it loses 1800

As a result, the merchant lost a total of 360

1. After Xiaohong bought the gift, she left: 4 (1-2 3), so she asked her mother: 4 (1-2 3) (1-2 3) = 36 yuan.

2. The original price of the money-making computer is 7200 (1+

The original price of the losing computer was 7200 (.).

Therefore, a computer that loses money is more expensive than a computer that makes money, and if it is the same 20%, it will end up being a loss.

(1) Set Xiaohong to X yuan.

x—（2x/3+（x—2x/3）2/3）=4x=36

2) Let one of them have a purchase price of x yuan, and the other has a purchase price of y yuan x+

x=6000

y—y=9000

Total purchase price: 6000 + 9000 = 15000

Total selling price: 2 7200 = 14400

Answer: The loss is 600 yuan.

4 (1-2 3-1 3x2 3)=4 1 9=36 yuan7200 (1+20%)=6000 yuan, make 7200-6000=1200 yuan.

7200 (1-20%) = 9000 yuan, loss 9000-7200 = 1800 yuan.

So the loss: 1800-1200 = 600 yuan.

1.Solution: Set up x people first.

2x+8(x+5)=80*3/4

2x+8x+40=60

10x=20

x=2A: 2 people will be arranged first.

2.Solution: Set it to be finished in x hours.

1/30*(3+x)+1/20*(3+3)=1(x+3)/30+3/10=1

x+3)/30=7/10

x+3=21

x=18A: It will be finished after 18 hours.

3.Solution: Set the discount to x

1+20%)x=1+8%

x = A: The price is 9% off.

y=(80-60)

20x-x-8000

19x-8000

2)19x-8000=106000

19x=114000

x=6000

A: The number of production pieces is 6000 pieces.

1 If the planned number of people is x, then 2x+(x+5)*8=80*3 4 solution must first arrange 2 people to do two hours, and then add 5 people to do eight hours.

2. Set the water volume of the pool to x, the discharge volume of A is x 30, B is not x 20, then the two pipes are opened at the same time for 3 hours, the discharge amount is 3 (x 30 + x 20), the B pipe is opened separately for three hours, the drainage volume is 3x 20, and the remaining water volume is 3 5x and the discharge time is 18 hours from pipe A.

3. If the purchase price is a, then a*(1+20%)*x-a=a*8%, the solution is x=89 off, 4y=(80-60)*

106000=(80-60)*Solution x=6000

1.Untie; Let's let x people do it first.

1/80xx2+8(5+x)1/80=3/41/40x+1/2+1/10x=3/4

1/8x+1/2=3/4

x=2A: Let 2 people do it first, and then add 5 people to do 2Untie; It takes x hours.

3（1/30+1/20）+1/20x3+1/30x=11/30x=3/5

x=18A; It takes 18 hours.

A: 9% off is required.

20x=yA: The number of pieces produced is 5300 pieces.

Solution: The sum of the number of sides of the two polygons is n-m+4, and when m=0, the sum is n+4

When m=1, the sum is n+3

When m=2, sum is n+2

After a reflection change on the x-axis, it is (-2x+y, 3x+2y), and after a reflection change on the y-axis, it is (-2x+y, -3x-2y), so -2x+y=3,3x-2y=-4

Get x= -2 7 y=17 7