Sixth grade math problems, urgent, urgent, and additional

The area of the first square is the square of (40 4), i.e., 100 square centimeters, and the area of the second square is half the area of the first square, i.e., 1 2, therefore, the area of the sixth square is.

100 * 1 2 * 1 2 * 1 2 * 1 2 * 1 2 = square centimeters).

1st, 2nd, 3rd, 4th, 5th, 6th.

Because the area of the second square is equal to the first square minus the four triangles with a base height of half the first square, and its area sum is exactly half of the first square, and so on...

So the area of the sixth square is:

40 40) 2 2 2 2 2 = 50 square centimeters.

With 40 times 40, it is equal to 1600 square centimeters. Then divide 1600 by 2, and divide by (6-1) times, that is, 5 times, and finally get 50 square centimeters.

The side length of the nth square can be.

40*（√2/2）^n

So the side length of the sixth square is 5cm

The area is 25 square centimeters.

Use the Pythagorean theorem to find the side length of the second square, find the area of the second square, see how many times its area is several times the first square, multiply this multiple by 6 times, and the result is.

The area of each square is 1 2 for the previous one, so 50 square centimeters is the answer right.

The teacher is 27 years old.

The number of years the teacher is older than the student is always the same.

If the teacher is x years older than the student, then:

1) When the student is 3 years old, the teacher is (3+x) years old; According to the title, the current age of the student is (3+x) years old;

2) When the teacher is 39 years old, the student is (39-x) years old; According to the title, the teacher's current age is (39-x) years;

3) Find the pattern: the current age of the student is (3+x); The teacher's current age is (39-x); We know that the number of years older than the student is always the same, and the teacher is always x years older than the student.

4) Knowing that the teacher is x years older than the student, the student's current age (3+x) is increased by x years, which should be equal to the teacher's current age (39-x);

Bulley equation: 3+x)+

x(39-x) solves: x

Current age of the student: 3+x

Age of the teacher: 39-x

years) The age difference between two people: (39-3) (1+2) = 12 years.

This teacher is now: 39-12 = 27 years old.

Students: 27-12=15 years old.

Set the small profit original x yuan, and the small red original (110-x) yuan.

4/5x+2/3（110-x）=80

2/15x+220/3=80

2/15x=20/3

x=50A: Xiaoli originally had 50 yuan of pocket money.

If there is something you don't understand, ask again, I wish you to learn and make progress and go to the next level! (

If Xiaoli has x yuan pocket money, then Xiaohong has 110-x yuan 4 5x + (110-x) 2 3 = 80

4/5x+220/3-2/3x=80

4/5x-2/3x=80-220/3

2/15x=20/3

x=50

There is a small profit of x yuan.

x*4/5+（110-x）*2/3=80

x*4/5+220/3-x*2/3=80

4x/5-2x/3=80-220/3

2x/15=20/3

x = 50 small profit turned out to be 50 yuan.

Let Xiaohong have x yuan, and Xiaoli has Y yuan.

System of equations x y 110

Two-thirds x four-fifths y 80

Solve the system of equations x 60 y 50

Adopt me, if you don't understand, you can ask.

Solution: Let Xiaoli be the original x yuan, then Xiaohong has (110-x) yuan 4 5x + 2 3 (110-x) = 80

4x/5+(220-2x/3)=80

12x+1100-10x)/15=80

2x+1100=1200

2x=100

x=50

Set a small profit of the original x yuan pocket money.

Then: 4 5x+2 3(110-x)=80

Solution: x=?

1 If the elder brother has x cards, then the younger brother has 3x 4 cards, x+3x 4=105

x = 60 brother 60 cards, location 45 cards.

That is, this piece of land has 4 hectares.

10,000 yuan = 7,500 yuan.

Therefore, the business tax should be paid 7,500 yuan this month.

18 black rabbits.

1 brother 105 (1 + 3 4) = 60 brother 105-60 = 45

2 7 3 (1-5 12) = 4 hectares.

3 15*5%=10,000 yuan.

4 Black rabbits 24*3 4=18.

1.Let my brother have x stamps, x+3x4=105 and x=602The land is set up with x hectares, and 5x 12 + 7 3 = x solution gives x = 43 15*5%=7500

4.Number of black rabbits = 24 * 3 4 = 18, number of all rabbits = 18 + 24 = 42

1. The younger brother's is 45, and the elder brother's is 60

Hectare. yuan, or you can write ten thousand yuan.

Only! ...Why is the question of the sixth grade so simple ...... this time?

1.According to the number of copies, it is solved like this: Brother and brother have a total of 4 + 3 = 7 copies, 105 7 = 15 sheets, this is one copy, the elder brother has 4 copies, that is, 15 * 4 = 60 copies, and the younger brother has 3 copies, which is 15 * 3 = 45 copies.

2.Seven-thirds (1-5 out of 12) if you're in sixth grade, you should understand that you end up with seven-two-hectare.

10,000 yuan = 7,500 yuan.

4.How many black rabbits are there? 24 * three-quarters = 18 pcs. It's so easy. It's not a bit of a stretch. Hehe.

1. If the number of philatelic records of the elder brother is x, then the equation of the philatelic number of the younger brother is 3 4x sheets as x+3 4x=105, x=60, 3 4x=45, so the philatelic number of the elder brother is 60 sheets, and the number of philatelic numbers of the younger brother is 45 sheets.

2. If there are x hectares in this land, then 5 12x hectares have been plowed in the morning, and the equation is listed as 5 12x+7 3=x, x=4

So the land has 4 hectares.

This month's tax payment is 10,000 yuan.

4. You can ask, how many black rabbits are there? Or how many rabbits there are in total.

The answer is that there are 18 black rabbits, and there are 42 rabbits in total.

1. The elder brother and the younger brother collected a total of 105 stamps, and the number of stamps collected by the younger brother was three-quarters of that of the elder brother. How many stamps do you collect?

Answer: 60 for the elder brother and 45 for the younger brother.

2. A farm tractor ploughs a piece of land in one day. Five-twelves of the field was ploughed in the morning and seven-thirds of the hectares in the afternoon. How many hectares is there in this plot? A: 4 hectares.

3. The turnover of a large hotel in a month is 150,000 yuan. If you pay business tax at 5% of your turnover, how much business tax should you pay this month? A: 7500 yuan.

4. There are 24 white rabbits, and the number of black rabbits is three-quarters of that of white rabbits, Answer: 18 black rabbits.

1A = 4, B =

3 There were 20 boys and 30 girls, and 1 boy was added, and now there are 20 + 30 + 1 = 51 boys.

4 100 kg.

5. A originally 6,700 yuan, B original 7,700 yuan.

1.4. Set the armor to x:

x + 4 5 x = solution x = 4, 4 80% =

2.1200 8 = 150 hours, 1200 6 = 200 hours, so the productivity per hour increases.

Assuming that the production efficiency is increased by x% compared to before the reform:

1200 6 - 1200 8) (1200 6) = x, x = 1 3 = about 33%.

3.At present, there are 21 boys and 30 girls, a total of 51.

Suppose there are x names for recruiting girls:

2 3 x + 1 = 70% x, the solution is x=30,30 70% = 21

4.100 kg.

Let's say this batch of fruit has x kilograms:

x (1-50%) 1-30%) = 35, and the solution is x=100

5.It turned out that A had 8,750 yuan and B had 9,250 yuan.

Suppose A has x-yuan:

x (1-20%)+x (1-20%)+400 = 14400, the solution is x=8750, 8750 (1-20%) 400] 5 4 = 9250

1.Let the number of armor be x

80%x+x=

x=480%x=

Answer: The number A is 4, and the number B is.

A: 25% increase in productivity per hour.

3.Set up the original female x people.

2/3x+1=70%x

7/10x-2/3x=1

1/30x=1

x=302/3x+1=21

30 + 21 = 51 (person).

A: There are 51 members in the choir right now.

4.This batch of fruit has a total of x kilograms.

1-50%-30%*50%]x=35

x=100A: This batch of fruits has a total of 100 kilograms.

5.There is a original existence of x yuan.

400+x(1-20%)+x(1-20%)=14400x=8750

400+x(1-20%) (1-20%)=9250A: A originally deposited 8,750 yuan, and B originally deposited 9,250 yuan.