Elementary school than the problem! Requirement has a detailed explanation 10

1) Because they are two alloys of the same weight, they can be regarded as 1, that is to say, the copper of the first block is 2 5, the zinc is 3 5, the copper of the second block is 1 4, and the zinc is 3 4, and the sum of copper is 13 20 and zinc is 27 20, so the ratio of copper to zinc in the new alloy is 13 27.

2) Same as (1) 3 4 + 4 5 31 20 for water and 1 4 + 1 5 9 20 for alcohol

The ratio of alcohol to water in the new solution after mixing is:

3) If the road taken by Xiao Ming is 1, then, the road taken by Xiao Ming is 1+1 5, if the time used by Xiao Ming is 1, the time used by Xiao Gang is 1+1 8, then the speed of Xiao Ming is: 1 (1+1 8) Xiao Ming's speed is: (1+1 5) 1

The ratio of Xiao Ming's small gang speed is:

1 Because they are equally heavy, they are directly copper; Zinc = (2+1); (3+3)=3;6=1;2

The second question is the same as the first.

3 Let Xiao Gang take the road 1, then Xiao Ming walked 1 and 1 5; Let Xiao Ming's time be 1, then Xiao Gang's time is 1 and 1 8, and the distance is divided by speed, so v Xiao Ming: v Xiao Gang = (6 5 divided by 1) :( 1 divided by 9 8) = 54; 40=27;20

Trust me, I'm a freshman in high school.

3 Let Xiao Gang take the road 1, then Xiao Ming walked 1 and 1 5; Let Xiao Ming's time be 1, then Xiao Gang's time is 1 and 1 8, and the distance is divided by speed, so v Xiao Ming: v Xiao Gang = (6 5 divided by 1) :( 1 divided by 9 8) = 16; 15

Brother Shitango spent 18, and his younger brother deposited 20 yuan and had 232 yuan.

Because the elder brother's savings were more than twice as much as that of the younger brother.13

The younger brother has (232-13) divided by 3 = 73 yuan.

It turned out that the search was 53 yuan.

My brother has 159 yuan.

It turned out to be 177 yuan.

and times the problem. and (multiples of 1) decimals.

Decimals, multiples, and large numbers.

Or. and decimal large numbers).

The problem of difference times. Poor orange is good (multiple of 1) decimal place.

Decimals, multiples, large round lead numbers.

Or. Decimal objects are different from large numbers).

Question 1:

It is advisable to have a base area of 20 square centimeters for a cylinder and 10 square centimeters for a cone.

And because the volume ratio of the cylinder and the cone is 3:2, the cylinder is 3 cm high, and the volume of the cylinder is: bottom * height = 20 * 3 = 60 cubic centimeters.

Let the height of the cone be y, then the volume of the cone = 10 * y * (1 3) 60 (10y 3) = 3 2 solve y=12cm The second question:

Because the ratio of the original money between Xiaogang and Xiaoqiang is 2:3, so let Xiaogang originally have 2x money, and Xiaoqiang originally had 3x money.

Solution x= So Xiaogang originally had 2x money, that is, 2x= yuan, I hope it will help you.

The height of the cone is 12 centimeters, and Xiaogang originally had yuan.

Question 1: Volume of a cylinder = base area x height.

Volume of the cone = (1 3) x base area x height.

According to the formula, we have already seen that the volume of cylinders and cones of equal height is 3 to 1, and the volume in the problem is 3 to 2, which means that the product of the area of the bottom of the cone and the height is twice the product of the area of the bottom of the cylinder and the product of the height.

At present, the ratio of the base area, the cylinder and the cone is 2 to 1, but the ratio of the base area to the high product is reversed, which means that the ratio of the cylinder and the cone, the height ratio is 1 to 4, so that the height of the cone is 3x4 = 12 cm.

Check that the ratio of the base area of the cylinder to the cone is 2 to 1, the ratio of height is 3 to 12, and the volume is (2x3) (1x12 3)= 6 4= 3 2, and it is exactly like this, the cylinder is 3 centimeters high, and the cone is 12 centimeters high.

The second question, Xiaogang and Xiaoqiang, the sum of the money remains the same, and the original money is 2 to 3, that is, Xiaogang's original money accounts for 2 5 of the sum of the two, and Xiaoqiang's original money accounts for 3 5 of the sum of the two;

After Xiao Gang gave Xiao Qiang yuan, the ratio of the two became 3 to 5, which is Xiao Gang's remaining money, accounting for 3 8 of the sum of the two, and Xiao Qiang's current money accounting for 5 8 of the sum of the two;

Let's make a general score, Xiao Gang originally accounted for 2 5 = 16 40 of the total sum, and now accounts for 3 8 = 15 40 of the total sum, which shows that Xiao Gang gave Xiao Qiang 1 40 yuan of the sum of the two, Xiao Gang's original 16 40, Xiao Gang's original money is yuan.

From another point of view, to do a test, Xiaoqiang originally accounted for 3 5 = 24 40 of the total sum, and now accounts for 5 8 = 25 40 of the total sum, and the yuan given by Xiao Gang accounts for 1 40 of the sum of the two, and the sum of the two is yuan.

Xiao Gang originally accounted for 2 5 of the total sum, which is 132x 2 5= yuan, and Xiao Qiang originally accounted for 3 5 of the total sum, which is yuan, and the original of the two people, 2 3, that's right.

Continue to check, Xiao Gang gave Xiao Qiang Yuan, yes ( ( ( 99 165 = 9 15 = 3 5, that's right, Xiao Gang Yuan Yuan, Xiao Qiang Yuan Yuan.

Solution: If there are x chickens, then there are x-25 rabbits.

2x+4×(x-25)=140

Solution x=40

So there are 40 chickens, and 40-25=15 rabbits. Because chickens have two legs and rabbits have four legs, this guess is based on the equation of the number of legs.

If the rabbit is disturbed by x, the chicken is x+25

2(x+25)+4x=140

2x+50+4x=140

6x=140-50

6x=90x=15

Answer: 15 rabbits and 40 chickens.

The solution with the equation is:

Rabbit = (140-50) 6 = 15

Chicken = 15 + 25 = 40

Rabbits are x, and chickens are branches.

4x+2y=140, x=y－25

Bring the second formula into the first formula, get.

4y jerk 100 + 2y = 140

y=40, then x=15

So 15 rabbits and 40 chickens.

Hello, I think this should be Sudoku. But I still helped you make it.

However, in addition to the fact that you can't repeat the numbers in the horizontal and vertical rows, Sudoku also has a requirement, that is, the number 1 in the 9 houses is also the number 1 9 can be repeated without potato lead (9 houses are 9 grids, which is the 9 grids enclosed by the thick line in my picture, and that arrangement is called 9 houses).