Help solve a few math problems to the process Please indicate the question number when answering the

Question 1. There are 16 + 15 + 21 = 52 (people) who only participate in one subject, then the students who participate in at least two groups have a total of 110-52 = 58 (people), and (52-16) + (61-15) + (63-21) = 36 + 46 + 42 = 124 (people), then there are 124-58 * 2 = 8 (people) who participated in three groups at the same time (58 should be multiplied by 2 because these 58 people participated in at least two groups, the extra number of people, That is, the number of people who also participated in the third group, that is, the number of people who participated in three groups at the same time).

Question 2. After the large cube with a side length of 10 cm is disassembled, only the small cubes on the side of the large cube are painted with more than one face, that is, the number of small cubes in this part is found. There are a total of 36 + 36 = 72 small cubes in front and behind this large cube, and there are 16 + 16 = 32 on the remaining borders on the left and right, so there are a total of 72 + 32 = 104 (this question requires some spatial imagination...).

Question 3. The boy's 10 11 is twice as many as the remaining girls, then the remaining girls are 5 11 as the boys, that is, the remaining 156-12 = 144 after removing 12 girls is the boy's (1 + 5 11), that is, 16 11 times, then the boy has 144 (16 11) = 99.

Question 1: 16 + 15 + 21 = 31 + 21 = 52 for those who participate in a group, 110-52 = 58 for those who participate in a group

There were 36 participants in the language group.

There were 46 participants in the English group.

There were 43 participants in the mathematics group.

There are x people in three groups.

58-x=(36+46+43-3x)/2

116-2x=125-3x

x = 9 with 9 people.

Question II: 64

Question 3: Male x x 12 + 10 x 22 = 156 x = 99 .

1 set x to participate in 2 subjects, y to participate in 3 then there is 2x+3y=121, x+y=58 and then calculated.

2 is on the edge and on the corner, 8 times 12 + 8 = ...

3 still sets x,y

You should be a primary school student.,I don't know if I've learned a binary equation.,If you haven't learned it, you shouldn't have seen this answer.。。。

Solution 1: Let only those who participate in all three subjects be A, B for Chinese and English, C for Chinese and Mathematics, and D for English and Mathematics.

21+a+d+c=63 Solution 3: Let the boy x and the girl y.

16+b+c+a=52 (1-1/11)*x=(y-12)*215+a+b+d=61 x+y=156

a+b+d+c=110-16-15-21 Quaternary equation you can solve, so you can find x y.

Solution 2: This is actually a permutation problem.

Let's start with the big cube, which is made up of four vertical edges and eight edges that intersect them, so at least two sides are actually dyed on the edges: 10*4+8*8= give me some hard work, okay?

There were 36 participants in the language group.

There were 46 participants in the English group.

There were 43 participants in the mathematics group.

There are x people in three groups.

58-x=(36+46+43-3x)/2

116-2x=125-3x

x = 9 with 9 people.

Question II: 64

Question 3: Male x x 12 + 10 x 22 = 156 x = 99 .

Analysis: The polynomial of the original transport brigade split to the old town.

5xy-3ab+bc-2) -2xy-bc+3ab-1)3xy-6ab+2bc-1, so the correct side-closed answer.

3xy-6ab+2bc-1) -2xy-bc+3ab-1)xy-9ab+3bc

1. Since the student mistook the minus sign as the plus sign of the Tong code, the correct answer should be a polynomial minus twice as much as the original answer.

Original integer = (5xy-3ab+bc-2)-(2xy-bc+3ab-1)=3xy-6ab+2bc-1

Result = (3xy-6ab+2bc-1) Answer - (2xy-bc+3ab-1) round = xy-9ab+3bc

(1) 3:24 a.m.

2) There are 1 female student and 3 male student, with an average of 82, and the total score is 328The average score for boys is 80, for a total of 240 points, so the average score for girls is 88 points.

3) Four-thirds of the way through? It's all over 1, and the question is wrong.

4) 3 hours and 9 minutes (

5) The mantissa of the number divisible by 2,5 must be 0, divisible by 3, and the sum of the remaining two numbers is a multiple of three, and it must be the largest, then it is 750,750 = 5 * 5 * 5 * 2 * 3, 6) A completes 1 6 per hour alone, and B completes 1 9 per hour alone. A and B do it for 2 hours, and complete 2 * (1 6 + 1 9) = 5 9

The rest of A is done alone, to (4 9) (1 6) = 8 3 hours (7) in the opposite direction, then after a minute, (100 + 120) * meters If the two do not meet, then A and B are 2750 + 150 = 2900 meters apart.

1.An hour and 60 minutes, two-fifths of an hour is 34 minutes, so 3:24.

2. Let the girl x person and the boy 3x person answer y then the total score is 80 * 3 x + y * x = 82 * (x + 3x) The result is 88

3. Make sure the topic is right 4 3 of the whole process and turn back???

Hour 9 minutes.

5, divisible by 5 mantissa must be 0 or 5 if it is 5 then not divisible by 2 so 0 then there is 4 5 7 left in order to have the largest number Therefore it must start with 7 Then it is 750 Prime factor 2 3 5 It's gone.

6. The total amount of work is x, then the speed of A is x 6, B is x 9, A and B cooperate for two hours, then it is x 6 * 2 + x 9 * 2, the percentage of work completed can be divided by x to be 5 9, then the remaining work of 4 9x divided by the speed of A can be 8 3

7. The two did not meet for 1 minute.

2) Minutes have passed.

The third question is changed to three-quarters of the whole distance.

Then a quarter of the distance is 4 kilometers, the distance is 16 kilometers, that is, 70 minutes, 12 kilometers, then 70 12*16 is the total time of 280 3 minutes.

1. 3 24

3.There is a problem with this question.

5. 750 2*3*5*5*56. 5/9 8/37.2900 or 2600

1.Question 3:24.

2.88 points.

4.Question 3:09.

1.Three and two-fifths of the hour = (3) hour (24) minutes 2The ratio of the number of girls to boys participating in a mathematics competition is 1:

3. The average score of this competition is 82 points, of which the average score of boys is 80 points and the average score of girls is (88) points. 3.The "Morning Star" Literary Society went to Yangzhou Slender West Lake to collect wind during the holiday.

The bus departed from the school, and four-thirds of the way through the journey took seven-sixths of an hour, and it was still 4 kilometers away from Slender West Lake. At this rate, how many hours does it take to complete the journey? How many kilometers is the distance from the school to Slender West Lake?

Seems to have a problem with the title) 4Hours = (3) hours (9) minutes 5Select three numbers from to form the largest three-digit number that is divisible at the same time, which is (750), and break it down into prime factors ( ).

6.For a project, it takes 6 hours for A to complete alone, and 9 hours for B to complete alone. A and B do it together for 2 hours, and complete the project (5 9), and the rest is done by A alone, and it will be completed (10 3).

7.A and B are walking in opposite directions from A and B at the same time, A travels 100 meters per minute, B travels 120 meters per minute, and the two are 150 meters apart after a minute. How many meters apart are A and B?

Analyze the various situations and answer) a get closer and closer to the meter; b. The farther and farther you go, this is not possible;

For the sunshine to be at its fullest, the area must be the largest.

Let the area be y, and the horizontal length of the word "目" is x

Then that one has a vertical length of 12-4x

Then the area is (12-4x)*x

In that case, it becomes a problem of finding the maximum value of a quadratic function, which shouldn't be difficult, right?

However, it should be noted that the definition field of x is scoped.

Width and length 3 first set the width to x and the length to y, 4x+2y=12; z=x*y, sufficient is the maximum area z=x(6-2x)=-2(

Set the transverse side a and the longitudinal edge b

Then we get 4a+2b=12, that is, 2a+b=6

And make the most abundant sunlight, that is, the area is the largest, that is, find the maximum value of ab.

ab=（6-2a）a=-2（a^2-3a）=-2（a-3/2）^2+9/4

That is, the area is the largest when a=, and b=3 at this time

That is, the length and width are...

1. Proof question: The square of (a b c) is known to be 3 (ab bc ca) and a, b, and c are all real numbers, and the verification is a=b=c

Certificate: (a b c) 2=(a 2 b 2) 2 (a 2 c 2) 2 (c 2 b 2) 2 2 ab 2ac 2bc

ab ac bc 2ab 2ac 2bc [when the (a2b 2) 2 ab relation is applied, a=b, equal. ]

i.e., left-style 3ab 3ac 3bc

Because, left 3 (ab bc ca), a=b, b=c, c=a, i.e., a=b=c

2. Determine the value of k so that the square of equation 8x - (k-1) x k-7 = 0 has.

1) Two real roots of opposite numbers (2) Two real roots whose product is equal to 1 (3) Two positive roots

Solution: Two roots are 16

1) Because, two real roots that are opposites of each other

x1 x2=-b/a=（k-1）/8＝0，k=1

2) Two real roots whose product is equal to 1

x1 x2=c a=1, i.e. (k-7) 8=1

solution, k = 15

3) Two positive roots

i.e., (k-9) (k-25) 0, k-25, or k-9

k-1±√[k-9）(k-25)]≥0，（k-1）^2≥k^2-34k 225,k≥7

Therefore, the value of k can be in the range of 7 k 9, or k 25

Question 1: Let log2x+1=y, then x=2 (y-1), so f(y)=2 2*(y-1), i.e. f(x)=2 2x-2

One has Yuan Yuan.

There are two pieces of Yuan Yuan.

Yuan Yuan Yuan Yuan three sheets have Yuan Yuan Yuan.

Yuan Yuan Yuan Yuan has Yuan Yuan Yuan.

Yuan Yuan Yuan. Yuan Yuan Yuan.

To sum up, there are 100 yuan, 50 yuan, 10 yuan, 200 yuan, 150 yuan, 110 yuan, 60 yuan, 20 yuan, 250 yuan, 210 yuan, 70 yuan, 30 yuan, 300 yuan, 260 yuan, 220 yuan, 170 yuan, 130 yuan, 160 yuan, 120 yuan, 80 yuan, and 40 yuan.

There are 21 types in total.