Mathematics and other possible topics Preparatory Junior High School .

If there are x red balls, then the white balls are 5 6x, the black balls are 1 4x, and the column formula is x+5 6x+1 4x=125

50 24x=125 x=60 Red balls are 60 white balls are 50 black balls are 15.

If the number of white balls: number of red balls = 5 : 6, number of red balls: number of black balls = 4 : 1

Number of white balls: Number of red balls: Number of black balls = 10:

12 : 3 There are 25 parts in total, one part is 125 divided by 25, each part is 5, so the number of white balls is 10 * 5 = 50 The number of red balls is 12 * 5 = 60 The number of black balls is 3 * 5 = 15 Answer:

Because the number of white balls: the number of red balls = 5:6, and the number of red balls: the number of black balls = 4:1

Then, the number of white balls: the number of red balls: the number of black balls = 10:12:3

So the number of white, red, and black balls is respectively.

If there are 5x white, 6x red, and (125-11x) black.

The red-black ratio is 4:1, i.e

6x:(125-11x)=4:1

Gives x=10

Each ball can be drawn.

Because white:red=5:6 red:black=4:1

So white:red:black=

So the number of white balls is: 5 (5+6+

The number of white balls is: 125 * (15 125) = 50 The number of red balls is 60, and the number of black balls is 15

The least common multiple of 3,4,6,8 is 24

Students in the fifth grade who participated in the tree planting were:

24 2 48 people.

The factors of 24 are 1, 2, 3, 4, 6, 8, 12, 24; The factors of 36 are, 2, 3, 4, 6, 9, 12, 18, 36.

So he should be 14 years old, 97 points, 3rd.

This is how it is written, it is very clear, this question is a test of the knowledge of prime number, composite number, prime factor decomposition, you just need to be able to separate, calculate it, first of all, 97 is a prime number can no longer be decomposed, only the result can be so big, so 97 is the grade. Then there is 2 3 7 left, so it has to match your age, you should not be 21 years old, you can only be about 14 years old, so it is 14 years old 3rd place instead of 21 years old second place.

1.A total of 4 groups were divided, each group of 12 people 4*12=48

2.(2 and 3) I forgot about it too.

3.The age is 14 years old, the score is 97, and the ranking is 3 * 97 * 14 = 4074

2) There are Y tickets for men's basketball, Y for football tickets, and 10-2Y for table tennis.

From the inscription, 1 000y+800y+500(10-2y) 8 000,1 000y 500(10-2y)

The solution is that y is an integer, so y=3 ∴10-2y=4．

Columns are not equal to equations: set up x sheets for men's basketball, and x sheets for football.

1000x+800x+500(10-2x)＜＝8000500(10-2x)＜＝1000x

Just solve it.

Old-fashioned, go search for it on the Internet yourself, there is an original question.

Chapter 1 Divisibility of Numbers.

Section 1 Integer and Divisible.

The meaning of integers and positive out.

Factors and multiples.

A number that is divisible.

Section 2 Decomposing Prime Factors.

Prime numbers, composite numbers, and decomposed prime factors.

Common Factor and Greatest Common Factor.

Common multiples vs. least common multiples.

Chapter 2 Scores.

Section 1 The Meaning and Nature of Fractions.

Fractions and division.

The basic nature of fractions.

Comparison of the size of the scores.

Section 2 Calculation of fractions.

Addition and subtraction of fractions.

Multiplication of fractions.

Division of fractions.

Interaction of fractions and decimals.

Fractions, decimals of four mixed operations.

Application of fractional operations.

Chapter 3 Ratio and Proportion.

Section 1 Ratios and proportions.

than the meaning. than the basic properties.

ProportionsSection 2 Percentages.

The meaning of percentages.

Percentage applied.

and other possible events.

Chapter 4 Circles and Fans.

Section 1 The circumference and arc length of the circle.

The circumference of the circle. The arc length of the second section is the area of the circle and the fan.

The area of the circle. The area of the fan.

1 Location.

2 Multiplication of fractions.

3 Fraction division.

4 rounds to determine the starting line.

5 percent.

6 Statistics. Reasonable deposits.

8 Total Review.

I don't know which set of textbooks you are, my previous catalog was like this)

Hello! Grade 6) Semester 2 Mathematics to Learn:

1。Application of percentages.

2。Cylinders and cones.

3。Proportion. 4。Determine the location.

5。Proportional and inversely proportional.

6。Problem-solving strategies.

7。Statistics. 8。Total review.

（1）x+30=

x+30=50

x=202)b is called a, c (the middle term).

3)4:9=24：x

x=9x24/4=54

You can also look at it this way: 4 becomes 24 and expands by 6 times, and 9 also has to be expanded by 6 times, i.e. 9x6 = 54

(1) (2) If a:b:c, which is b squared = ac, then b is called a and c (the middle term of the proportion).

3）4:9=24：x

x=9*24 4=54 (product of inner term = product of outer term).

The answer here is more complete, so let's refer to it!