Solve math problems! 3 oh, 3 math problems!

1) 29 people, [(42-32)-4]+[42-35)-4]+4 Explain that 10 people can ride bicycles, 7 people can skate Because there are 4 people, they will subtract 4 people from both, so there will be 6 people who can only ride bicycles, and 3 people who can only skate

There will be 4 people in both cities, and it will not be 42 minus 6 people, minus 3 people minus 4 people.

2) Let A, B, and C be xyz, then 3x=4y, 2y=z, z-x=60, the ternary equation will come out and understand y=90

3) Let the distance be s, the speed of the passenger car is x, and the speed of the truck is the equation of y 15x=s, 10y=s, then the formula.

It took T time to set up the encounter again

x+y)t=s 2 yt-xt=25 3 formula.

Replace 1 generation as 2 and then 1 as 3.

The answer is obtained by the above 2 equations to s=125.

1.Cyclist = 42-32 = 10

Skating = 42-35 = 7

Cyclist or Skating = Cyclist + Skating - Both = 10 + 7-4 = 13 Neither = 42-13 = 29

2.Set up a basket with x balloons.

Then the number of balloons in basket A x * 4 3, the number of balloons in basket C 2 * x

x*4/3+60=2*x

x=90B basket contains 90 balloons.

b The two places are x kilometers apart.

Then the speed of the passenger car is x 15, and the speed of the truck is x 10 when the two cars meet = x (x 15 + x 10) = 6 hours.

x/10*6-x/15*6=25

x = 125a, b and the two places are 125 km apart.

1. 32+35-x+4=42

2.Solution: If A is x, B is y, then C is x+60.

Get: 3x=4y

2y=60+x

Solution. A has 120, B has 90, C has 180.

3.Solution: Set the total length of x kilometers. Then the truck is gone. The bus is OK.

(x 10)= (x 15).

The total length of the solution is 125 kilometers.

Question 1:

The length of the fence is also the circumference of the semicircle!! The perimeter is divided by the length of the radius!! The area of the semicircle is 1 2 times the square of the radius!

Question 2: 102*70-90*50=3600m square.

Question 3: Length = 1 2*6 5*1 2=3 10

1.The front-to-back efficiency ratio is 1:(1+20%)=5:6, so the time required before and after is 6:5

The actual time is 30*5 6=25 days.

It can be 30-25=5 days in advance.

2.Actual 25 5 = 5 tons per day.

There are 30 days in September, and the actual production can be 5 * 30 = 150 tons can be overproduced: 150-120 = 30 tons.

3.When A runs 100 meters, B runs 100-20 = 80 meters, and C runs 100-30 = 70 meters.

So the velocity ratio of Ethylene-Propylene is 80:70=8:7

When B reaches the finish line, C runs: 100*7 8=m.

C is still from the end point: meters.

Solution: (1) 3x+2a=2

3x=2-2a

x=(2/3)-(2a/3)

The title says "The solution of equation 3x+2a=2 is a-1".

2/3)-(2a/3)=a-1

2-2a=3a-3

5a=5a=1∴a=1

2) In the past three decades (1978-2007), the number of poor rural people has decreased from more than 250 million to more than 20 million.

The average annual decrease in population = (250000000-20000000) 307.67 million (3) 1) Draw a picture and find a pattern.

Scissors 1 knife to get 4 ropes.

Scissors 2 knives to get 7 ropes.

Scissors 3 knives to get 10 ropes.

Number of rope roots = 2 + 3 (n-1) + 2 = 4 + 3 (n-1) (n represents the number of times you cut it) 2) to get 100 ropes.

Then 4+3(n-1)=100

n Impossible (impossible to cut half a knife).

3)4+3(n-1)=2008

n=669 means that if the graph is 1"z"Words, then cut 669 knives Now the title says that only 223 knives were cut, a total of 669 223 = 3"z"The word m 2=3

m=6

1) A from the wide side of the horizontal cut is equal to B from the long side of the vertical cut of the surface area, the cut of the two cuboids of the surface area than the original cuboid = 10 * 4 * 2 = 80 cm2

2) 1*1*1*8=8=2*2*2, that is, the top four small cubes, the bottom four small cubes, the surface area is the smallest, this is the cube, the area of the cube is the smallest. Area = 6*2*2 = 24 cm2

1.A factory processes 180 parts, 9 of which are scrap. What percentage of the total number of parts are scrapped?

2.A supermarket held a festival ** activity, set up separately.

There are several first, second and third prizes. Thereinto.

The number of first and second prizes accounts for one-half of the total number of people.

The number of second and third prizes accounts for 8/9 of the total number of people.

What percentage of the number of first and third prize winners is the total number of people?

3.There are 32 cars and motorcycles parked in a parking lot, and the total number of wheels for both types of cars is 100.

1、**：171/180=95%

Scrap: 9 180 = 5%.

2. Second prize: 1 2 + 8 9-1 = 7 18

Answer=1-7 18=11 18

3. There are x motorcycles and 32-x cars.

2x+4（32-x）=100

The solution is x=14

32-x=18

14 motorcycles and 18 cars.

(1) 1260 7 8 1440 (yuan) 1440 1260 2700 (yuan).

2) 180 (8 7) 180 (yuan) 180 (8 7) 2700 (yuan).

3) 84 (4 2 3 2) 6 (cm) 6 4 24 (cm) 6 3 18 (cm).

24 18 432 (square centimeters).