Six math problems, math problems in the second volume of the sixth grade

There are x number of boys.

The girl's 2 3 is 20 less than the boy's 4 5, i.e. the girl's 2 3 = 4x 5-20 so the girl = (4x 5-20) (2 3).

So 465=x+(4x 5-20) (2 3)=x+(4x 5-20)*3 2=x+6 5x-30

11 5x=495 Solve x=225

So there are 225 boys.

Solution: There are x number of boys.

4/5x-20=（465-x)×2/3

4/5x-20=310-2/3x

22/15x=330

x=330÷22/15

x=330×15/22

x=225A: There are 225 boys.

Solution: If there are x boys, then there are (465-x) girls. (4 5) x - 465-x)2 3 = 20 (4 5) x - 465 *2 3 + 2 3 x = 20 ( 22 15) x = 20 + 310 x = 330 *(15 22) x = 225 A:

There were 225 boys.

Solution, let's say there are x number of boys and 465-x number of girls.

2/3（465-x）=4/5x-20

x = 225 boys.

If there are x boys, then there are (465-x) girls

2\3*（465-x）+20=4\5*xx=？

The side length of the original square: 120 4 = 30 (meters).

The original square area: 30x30 = 900 (square meters) and the current square area: 900x2 = 1800 (square meters).

Possible! The area is exactly doubled. The original area is 30 30 = 900, and the enlarged area is 1800

It can't be, because if it's 900 2 = 1800

So, it can't be.

Assuming that they are all large barrels, then they can hold 10*54=540 kg.

And the actual less is 540-450 = 90 kg.

Each keg contains 10-5 = 5 kg less than the vat.

Then the keg has 90 5 = 18 pcs.

Then there are 54-18 = 36 vats.

If they are all small kegs, they can be filled with 5*54=270 kg.

Each additional vat will be 10-5 = 5 kg more than 270 kg, now weighs 450 kg, 450-270 = 180 kg more than 270 kg, so, the number of kegs = 180 5 = 36 barrels

Number of vats = 54-36 = 18 barrels.

Set up x large barrels and y small barrels.

From the problem: x+y=54 Equation 1

10x+5y=450 Equation 2

Multiply both sides of Eq. 1 by 5 to get: 5x+5y=270 Eq. 3 (this step is to subtract y

Eq. 2-Eq. 3 gets: 5x=180 gives x=36 then y=54-36=18

Therefore, there are 36 large barrels and 18 small barrels.

Let the large barrels be x and the small barrels be 54-x, so 10x+5(54-x)=450

The solution is x=36, so get through 36, and the child 54-36=18

Set up x large barrels and y small barrels.

10x+5y=450

x+y=54

The solution is x=36 y=18

If there are x large barrels and y small barrels, there are:

x+y=54,10x+5y=450

x=36 and y=18 can be obtained

Set up x large barrels, y small barrels, x+y=54, 10x+5y=450Solve systems of equations.

x=36 y=18

Let there be x vats, then there are 54-x kegs, and the equation is 10x+5(54—x)=450

Solution: x=36 So there are 36 large barrels and 18 small barrels.

Let there be x large barrels, then there are 54-x small barrels, and list the equation: 10x+5(54—x)=450.

Let the small barrels be x, the large barrels be (54-x), and the column equation is 5x+10(54-x)=450, and then solve it.

1.A and B are 440 kilometers apart. A car travelled 240 kilometers in 3 hours from A to B. According to this calculation, how many hours can you reach B?(Proportional solution).

2.An engineering team laid a section of sewer, which was originally planned to be laid 20 meters per day and completed in 15 days. In fact, 5 meters more are paved every day, and how many days are the tasks actually completed?(Proportional solution).

3.A house needs to be paved with square bricks, and 96 square bricks with a side length of 5 decimeters are used(Proportional solution).

4.There is a piece of copper and zinc alloy, the weight ratio of copper and zinc is 2:3, if you add 6 grams of zinc, the weight of the new alloy is 36 grams, find:

1) How many grams of copper and zinc are in the original alloy?

2) The weight ratio of copper and zinc in the new alloy

5.A bottle of oil is eaten for the first time 1 5, and the second time you eat the remaining 3 4, at this time there are 1 5 kilograms in the bottle, how many kilograms of this bottle of oil is there?

Answer: 440 = 3:240

2.（15+5）*x=20*15

4.(1) The weight of zinc in the original alloy is x grams.

36-6-x）：x=2：3

2) 18 g of zinc from the first inquiryCopper 12g weight ratio = 12: (6 + 18) = 1: 2

Solution x=1

You can find the question and help you come up with the answer, and I forgot what I learned in the second book of the sixth grade.

If you take 9, maybe three of each of the three colors, it is not guaranteed that there are two pairs of small sticks of the same color, if you take 10, the number of small sticks of at least one color according to the principle of drawer is not less than 4, so it is guaranteed that there are two pairs of small sticks of the same color.

10 sticks; (10+10+10) 3=10 Why is this difficult, it can't be so lucky, 10 sticks are all the same color, or it's just two colors, right?

(1) (12 12 + 12 16 + 12 16) 12 = 1056 (square centimeters).

12 square centimeters).

12 square centimeters of 2).

1056+ cm²).

square meters) 2) 30 50 yuan).

(1) (12 12 + 12 16 + 12 16) 12 = 1056 (square centimeters).

12 square centimeters).

12 square centimeters of 2).

1056+ cm²).

square meters) 2) 30 50 yuan).

12* Paint for one lamp holder.

12*16*4+12*12*2=288+868=1156 1156-[(12 2) squared]*?

12* Paint for one lamp holder.

Given the unknowns, there are x people who subscribe to the elementary school days, and y people who subscribe to the elementary school world, and there are 40-x-y people who subscribe to both.

You can find out if you want to find the largest of the x, y, and 40-x-y numbers, i.e., how many students subscribe to the same newspaper.

Assuming that x is the smallest, it should satisfy x>=y and x>=40-x-y, then it can be solved: x=40 3, but the number of people cannot be decimals, so take x=14, then y=14, that is, there are 14 people who subscribe to the primary school era, 14 people who subscribe to the world of primary school students, and 12 people who subscribe to both books, and the answer is that at least 14 people subscribe to the same type of newspapers and periodicals! You can verify that it's correct.

40 2=20 Because someone can order two copies of 20+1=21 (people) because one of them must have answered the same kind of newspaper as the previous person: at least 21 of them have subscribed to the same type of newspaper.

40/2=20

At least 20 students subscribe to the same type of newspaper.

40÷2=20

At least = 20 + 1 = 21 people.

Use 40 2 to get 20 first, and you have to add one because it's at least.

Hello, I'll help you out.

Explanation: Treemap:

Draw a score arrow under these two items

Underneath each arrow there are 2 possibilities.

You can see that there are 2 repetitions

The probability is calculated that there are no four arrows and one repeat subscription, and 10 40 (the probability is seen in the figure) is 10 people. Equation: (2+2+4) divided by 40=10 40 10 of them is 10.

Please adopt Thank you.

There are 40 students, and each student will have 2 possibilities. So there are 80 possibilities. And out of these 80 possibilities, 2 repetitions. The second tree is obtained, and there is a repeat every 4 squares. So, according to the probability, it should be the same as 10 students.

Is this a sixth-grade question for you? I haven't finished the question.

Because it is at least, the more students are ordered, the fewer the number of students, so 40 2 = 20, it should be possible to order one, so 20 + 1 = 21I guess I can get it.

40 2 = 20 people, because it is at least, so to add the name is 2 kinds of order, to add at least 1, so it is 21 people with the same kind.

40÷2=20

At least = 20 + 1 = 21 because the teacher wants to add 1, I have done it.

Hammer volume = sh 3 = *15 * 15 * 15 3 = 1125

Converted to cup drop volume Roll out h=1125 25*25*=

All you have to do is calculate the volume of the conical hammer and divide it by the bottom area of the cylindrical glass, and the answer seems to be 9

After calculating the volume of the steel hammer, calculate it according to the cylinder with a bottom diameter of 50, know the volume = the volume of the steel hammer, know the diameter of the bottom surface, and find the height.

If the distance of the mountain road is regarded as 1, then 1 10 is the time when the car goes uphill, 1 15 is the time when the car goes downhill, and 1 10 + 1 15 is the time when it goes up and down the hill, so the average speed of going up and down the mountain is: (1 + 1) (1 10 + 1 15) = 12

Total time: 1/10 + 1/15.

Then the average speed is 2 divided by (1/10 + 1/15), note that the average speed must be divided by the total distance by the total time, and the average of the two speeds cannot be directly calculated.