Grade 6 Math Problem 5 Reward, Urgently Needed

The Science and Technology Museum opened at 9:00, Xiaohong walked from home to the Science and Technology Museum at 8:30, and at 8:50, she completed 5/7 of the whole journey.

1) At this rate, will Xiaohong be able to arrive before the Science and Technology Museum opens?

Every minute, the whole journey.

The line is required for the whole process.

1 1 28 28 points.

8:30 28 min 8:58

Little Red was able to arrive before the Science Museum opened.

2) When did she arrive? Please explain why.

Every minute, the whole journey.

The line is required for the whole process.

1 1 28 28 points.

The arrival time is.

8:30 28 min 8:58

Half an hour in total, 30 minutes; He walked 20 minutes, which is 2/3 of 30 minutes, and 5/7 of the time; Five-fifths of sevenths is two-thirds of them, so he can walk.

20 points go 5/7! Just 4 minutes to walk 7 times the way!

Walk 1/7 in 4 minutes!

So it takes 28 minutes to walk the whole way!

20 points go 5/7! Just 4 minutes to walk 7 times the way!

Walk 1/7 in 4 minutes!

So it takes 28 minutes to walk the whole way!

So reachable!

1 28 per minute of walking

The remaining 2 7 journey time: 8 minutes.

That is, arrive at 8:58 a.m.!

1) At this rate, Xiaohong can arrive before the science and technology museum opens 2) She arrived at 7:58, reason:

Because Xiaohong walked from home to the Science and Technology Museum at 8:30, at 8:50, she completed 5/7 of the whole journey

It can be obtained that 5 7 is 20 (5 7) = 28 in 20 minutes, so it takes 28 minutes to complete the journey.

Solution: 1) 50-30 20 (min).

It takes 20 (5 7) 28 (min) 28<30 to complete the journey, so you can get there.

So she arrived at 8:58.

It took 5/7 of the total time taken to walk in 20 minutes and 20 (5 7) = 28 minutes. That is, Xiaohong still has to walk for 8 minutes to get to the Science and Technology Museum, and Xiaohong arrives at the destination at 8:58I can arrive before the door opens.

1.Let the age of A go to x, and C is 38 and B is 2x

3x＋38＝113x＝25

The answer is 42, based on the total number of students per class"m"

If Class A participates in 1, then Class B does not participate in 3

If Class A does not participate, then Class B participates in (M-1) 4(M-1) 4+3=M

m=11/3

Those who did not participate in Class A were 11 3-1 = 8 3

Class B did not participate in 3

The number of students in class A who did not participate in the math group is 8 3 3 = 8 9 of the number of students in class B who did not participate in the math group

Inspection: The total number of people is 11

A participated in 3, not 8

B participates in 2 and does not participate in 9

2.If the person who does not participate in class B is x, then the person who participates in class A is x3, and the person who does not participate in class A is y, and the person who participates in class B is y 4

x+y/4=x/3+y

x*2/3=y*3/4

y/x=2/3/[3/4]=8/9

Answer: The ratio of those who did not participate in Class A to those who did not participate in Class B is 8:93Class A participates = Class B does not participate in 1 3

1 4 = Class B who did not participate in Class A.

Class A participated + Class A did not participate in 1 4 = Class B participated + Class B did not participate 1 3 Due to the equal number of students in Class A and Class B.

Therefore, the number of people in class A - (those who participated in class A + 1 4 who did not participate in class A) = the number of people in class B - (those who participated in class B + 1 3 who did not participate in class B).

Those who did not participate in class A (1-1 4=3 4) = those who did not participate in class B (1-1 3=2 3).

Those who did not participate in class A Those who did not participate in class B = (2 3) (3 4) = 8 9 The ratio of the number of people who did not participate in class A to the number of people who did not participate in class B is 8:9

Let A, B, and C be a, b, and c, and let A be half the age of B before x years ago, and C will be 38 years old, and when B will be half the age of C before Y, A will be 17 years old. Then the equation 1 is obtained from the question condition, a+b+c=113

X years ago, A is a-x, B is b-x, C is c-x, a-x=1 2(b-x), c-x=38, then 2a-b=x, x=c-38, that is, 2 formula, c+b-2a=38

Y years ago, A is a-y, B is b-y, C is c-y, according to the conditions, a-y=17, b-y=1 2 (c-y), sorted out 2b-c=y, y=a-17, that is, to get 3 formulas, a+c-2b=17, from the above three formulas can be solved a, b, c, I don't know how to calculate and ask me again.

ps: a+b+c=113, b+c-2a=38, b+c=113-a=38+2a, the solution is a=25, that is, A is now 25 years old.

a+b+c=113, a+c-2b=17, a+c=113-b=2b+17, the solution is b=32, that is, B is now 32 years old.

So C is now 56 years old.

If you can use a system of equations, it is easy to solve!! I don't know if it's okay??

Train the equations, do it yourself, and have enough food and clothing.

The column binary equation is just that.

30 Answer: Equal to half a circle. 25 2= A:

The diameter is 25cm, and the radius is.

Diameter 30

The circumference rolls half a turn.

The formula for calculating the circumference of a circle is: d=2pi*r=2*cm, and the rolling circle tree is =

So the hoop rolls in a circle, that is, half a circle.

1.Distance rolled = circumference of the hoop and number of rolling laps, so, number of rolling laps = distance covered by the circumference of the hoop.

circle (the appearance of the rolling meter is more in line with the actual point).

2.Because the circumference of the circle is c= d or c=2 r, d=c, r=c2d=c=

r=c÷π÷2=

1.The radius and height of the bottom surface of a cone are equal to the edge length of a rectangle, and the volume of this rectangle is known to be 30 cubic centimeters, and the volume of this cone is (10 cubic centimeters).

2.A cuboid and a cone are equal in volume, and if the base area of the rectangle is two-fifths of the base area of the cone, then the height of the rectangle is the height of the cone (5 6).

3.A four-decimal place is accurate to the percentile, then the maximum of this four-digit decimal place is (, and the minimum is (.

4.The store is a shoe factory consignment, the two sides agree as follows: the number does not exceed 200 pairs, the consignment cost is 8 of the total sales, more than 200 pairs, the consignment cost is 10% of the total sales, and the consignment cost is 9990 yuan after a stage of consignment is known.

If the selling price of each pair is a two-digit prime number, then the selling price of each pair is (37 yuan).

5.The three small sticks of group (b) should not be connected end to end in a triangle. (Unit: cm).

4,5 b. 4,5,9 c. 7，13，19 ,30,42

The following is the process of solving the problem.

1.The number of the Communist Youth League in the third class of the eighth grade was originally a quarter of the number of non-Communist Youth Leagues, and later four more people joined the League, and the number of the Communist Youth League accounted for 30% of the total class at this time, how many people were in the third class of the eighth grade? (The number in this question is incorrect, and it has been modified).

40 people. 2。If the two teams cooperate, the construction will start on July 26 and can be completed by the end of July.

6 days to be completed at the end of the month.

3.At a gala, 100 students won tickets with labels ranging from 1 to 100. The moral rules for awarding prizes according to the ticket tag number are as follows:

The tag number is a multiple of 2 and rewards 2 notebooks.

The tag number is a multiple of 3 and rewards 3 notebooks.

The tag number is both a multiple of 2 and a multiple of 3, and the prize can be claimed repeatedly.

All other tags will reward 1 notebook.

Q: How many notebooks should I prepare for this party?

232 copies.

10π5/6

495b1.Set up the original x people.

x=36 for a total of 36 people.

2.A does 1 15 per day, B does 1 10 per day, A and B can cooperate every day to complete (1 15 + 1 10) = 1 66 days to complete, that is, it can be completed on July 31, and it can be completed by the end of JulyMultiples of 2 are 50 2x50 = 100 copies of 3 multiples of 3 are 33 copies 3x33 = 99 copies.

Multiples of 6 16 pcs.

There are still 100 - (50 + 33 - 16) = 33 numbers left, and a total of 99 + 100 + 33 = 232 books need to be prepared.

Poor kid who would do such a difficult topic.

First of all, the length of the bus bar is not counted, and the side area of the cone is according to the formula of a triangle (which is a simple calculus point of view), that is, it is multiplied by a coefficient of one-half.

The side area is calculated as the length of the bus first, and the knowledge of right triangles is used to square 8 + 15 squared = the square of the bus (which can be set to l).

Busbar l=17

The side area is the circumference of the bottom circle multiplied by the length of the bus bar and then multiplied by half is 2xpix8x17x1 2=136 pi, when pi is taken, the side area is.

The surface area is the area of the side area plus the bottom circle.

The area of the bottom circle is the square of pi r, which is 64 pi, and the surface area is 200 pi, and when you take pi, the surface area is 628, and the second question.

In the beginning, the surface area of a large cube is 6x6x6=216, and the total area of a small cube is 6x2x2x2x27=648, and the increased area is 648-216=432 (square centimeters).

1. Have you made a mistake, the side area of the cone is to use 2 3=12 of the busbar

Side area x15x15x( x4x2 x15x2)=60 Surface area x4x4+ x15x15x( x4x2 x15x2)=16 +225 (4 15)=76

A total of 27 were sawn.

27x6x2x2-6x6x6=432

1. If it is a cylinder, it can be done, but not a cone.

S side area = 1/2 of d H = 2r 15

I forgot the surface area formula Sorry.

The next question will not.

Question 1: Volume: 8*8*

Question 2: 27x6x2x2-6x6x6=432

The side area is, and the surface area is.

The surface area increased by 144 square centimeters.