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1>.At this time, the driving time is 2 hours, and A needs 3 hours to reach the midpoint, so A can walk 30 kilometers per hour.

The distance between station A and B = 30 * 6 = 180 km.

2>.It turned out that the quality of the grain stored in warehouse B was 11 23

Now A is 1 9 less than B, so A is 8 9 of B, and B accounts for 9 17 of the total mass Total mass = 24 (9 17-11 23) = 9384 394 B's original mass = total mass * 11 23 = 2244 1973>If B repairs 3 8, then the efficiency ratio of A and B to build the road is 5:3, and the ratio of time spent is 3:

5. If B is repaired alone, it will take 16 * 5 3 = 80 3 (days), so the road is a kilometer).

1.4 2=2 (hours) 2 6=1 3 1 2-1 3=1 6 30 1 6=180 (km).

24 20 391 = 2346 5 (tons) 2346 5-24 = 2226 5 (tons).

3.5 8 1 16 = 10 (days) km) 1-5 8 = 3 827 3 8 = 72 (km).

The first question is set to be full length x

x/2-x/3=30

The idea of the equation x = 180 is that half of the distance minus a third of the distance is equal to 30 kilometers.

A little more rigorous can also be listed.

x/2+30+(x/6)*2=x

Because it takes 6 hours for the bus to walk the whole way"x/6"On behalf of the speed of the bus, that is, the distance traveled per hour, why should it be multiplied by 2, because it takes 4 hours for the truck to walk the whole way, and of course it is 2 hours to walk halfway, so the bus also walks for two hours at this time.

It is recommended to draw a simple diagram first for the route topic to straighten out your thinking.

Solution: 56 ml = 56 cubic centimeters, then the bottom area of the container is 56 8 = 7 (square centimeters).

Since the height of the water surface in the container is only 4 cm after the cylinder is removed, the volume of the overflow water is 7 * (8-4) = 28 (cubic centimeters), that is, the volume of the part of the cylinder immersed in water is 28 cubic centimeters.

Due to the height of the cylinder and the height of the container, the volume of the cylinder immersed in water is not all the volume of the cylinder, but only a part of the volume of the cylinder.

So the height of the cylindrical part immersed in water is equal to the height of the container is 8 cm, then the bottom area of the cylinder is 28 8 = square centimeters), so the volume of the cylinder is cubic centimeters).

Combined, it is: 56 ml = 56 cubic centimeters.

56 8 = 7 (square centimeters).

7*(8-4)=28 (cubic centimeters).

28 8 = square centimeters).

cubic centimeters) A: The volume of a cylindrical rod hanging is cubic centimeters.

56 ml = 56 cubic centimeters.

56 2 8 = square centimeters.

Cubic centimetre.

56 8 = 7 square centimeters (base area of the volume of the cylinder. ）

7*4=28 cubic centimeters (the volume of spilled water, that is, the volume of the sticks.) ）

A: The volume of the wooden stick is 28 cubic centimeters.

1. Solution: (1) Set the mixed doubles for x games.

x+2（x+4）+2（x+4+4）=64

Solution: x=8

A: Mixed doubles was played for 8 matches;

2) Mixed doubles: 4 8 = 32 (person-times).

Men's and women's doubles: 4 (8+4) 2=96 (person) Men's and women's singles: 2 (8+4+4) 2=64 (person) 32+96+64=192 (person).

A: A total of 192 people participated in all competitions.

2. Solution: (40 1 2+50 1 2) (50-40)=hour) 40 (km).

Answer: The distance between A and B is 200 kilometers, and the driving time of the car here is hours.

Because a chicken has 2 feet and a rabbit has 4 feet, now there are 60 more chicken feet than rabbits, and if you replace these extra chicken feet with rabbit feet, it will be 15 rabbit feet. Therefore, if you add 15 rabbits, then the number of chickens and rabbits will be equal, so that 45 15 60, there should be 40 chickens and 20 rabbits in these 60, and then don't imagine the 15 rabbits added later, there will be 5 rabbits left. The result was 40 chickens and 5 rabbits.

The hypothetical method assumes that all 45 are chickens, and that there are more chicken feet than rabbit feet: 45 2 = 90 chickens.

For every 1 chicken decreased, 1 rabbit was added, and the difference between chicken feet and rabbit feet decreased: 2 + 4 = 6 rabbits were: (90-60) 6 = 5 rabbits.

Chickens have: 45-5=40.

...First of all, there are x chickens, then the rabbit is 45-x, 2x-4*(45-x)=60, and x=40, 45-x=5, so there are 40 chickens and 5 rabbits.

It should be 60 less.

Chickens x and rabbits 45-x only.

2x=4(45-x)-60

x = 20 chickens and rabbits, 20 each, 25 chickens.

60/2=30

When the chickens and rabbits have equal feet, the chickens and rabbits have a total of 45-30 = 15.

Rabbits have 15 3 = 5

Chickens have 45-5=40

A barrel of oil used a quarter of the first time, 20% of the total for the second time, and there are 110 kilograms left in the barrel, how many kilograms of oil is in this barrel?

1/4x+3/4*20%x+110=x

8/20x+110=x,110=12/20x

x=110*20/12

A task needs 5 hours to complete alone, B needs 8 hours to complete alone, A does 1 hour first, B joins the joint work, and when the task is completed, how many hours does B do?

Xiao Ming walks 20 meters per minute up the mountain and 30 meters per minute when he goes down, what is his average speed up and down?

The two cities are 225 kilometers apart, a passenger car and a truck drive out of the two cities at the same time, meet in five hours, the ratio of the speed of the truck to the speed of the bus is 9:11, how many kilometers does the passenger car travel per hour on average?

A 110 (1-quarter-20 percent).

2 1-1 5=4 5,4 5 (1 5+1 8).

Three (30+20) 2

IV 221 (9+11)=

1.Solve the original x kg of this barrel of oil, x-(25%x+20%x)=110 solution: x=200

4 5 (1 5 + 1 8) The final result is the time for B to do it.

3.The total distance of the solution is x m x 19-20 = x 29 + 204Passenger car x km hour truck y km hour (x + y) * 2 5 = 225

9x=11y

-1/4=3/4 3/4-20%=11/20 110/（11/20）=200kg

2. If the work as a whole is 1, then the work efficiency of A is 1 5, the work efficiency of B is 1 8, A completes the work of 1 5 first, and there are 4 5 left, which is completed by A and B together, then the column formula (4 5) (1 5 + 1 8) = 32 13 hours.

3. The average speed is (20+30) 2=25 meters per minute 4, and the speed of the truck is 9x, and the speed of the passenger car is 11x

The column equation 9x* is solved to x= so the speed of the passenger car is 11*

1 set a kilogram a = 200 2 set a hour 1 5 + (1 8 + 1 5) a = 1 a = 13 32

3 25 4 Let a (9a+11a)2 5=225 a=223 8

1. Rectangle volume = 12 * 4 * 4 = 192 cubic decimeters; Area = (12 * 4 + 12 * 4 + 4 * 4) * 2 = 224 square decimeters.

2. It is the least common multiple of 6 and 8 24

3. It is the greatest common divisor of 36 and 48 12

4. Male students account for 31/40; Girls make up 9 out of 40

The ratio of boys to girls is 5:6, that is, there are 5 boys and 6 girls in 11 students, and the total number of students is between 40 and 50, and only 44 is a multiple of 11, so the total number is 44. Boys = 44 * 5 11 = 20 Girls = 44 * 6 11 = 24 people.

There are 20 boys and 24 girls.

Answer: 44 total. 20 males 24 females Because 5:6 is divided into 11 parts40 50Only 44 is a multiple of 11, only 44 is divisible, and the number of people can be an integer.

20 boys and 24 girls

The ratio of male to female students is 5:6, then the total number of students in the class must be a multiple of 5+6=11, and there are only 44 between 40 and 50, so the total number of students is 44, so there are 20 boys and 24 girls

Solution: Suppose the number of students in a class is 44, then.

Number of boys: 44 [5 (5+6)]=20 (person).

Number of girls: 44-20=24 (people).