1. How many students are there in a class? If there are 4 students in each room and 20 students have no dormitory. If there are 8 people in each room and one room is not full, please try to find out the number of dormitory rooms and class size.
Bao Xiao and his parents are playing on the seesaw in the playground. His father weighs 72 kilograms and sits at one end of the seesaw. Bao Xiao, who weighs only half as much as his mother, sits at the other end of the seesaw with his mother. At this time, his father's feet were still on the ground. Later, Bao Xiao borrowed a pair of dumbbells weighing 6 kilograms and put them at the end where he sat with his mother. As a result, Bao Xiao and his mother escaped from danger. Guess how much Bao Xiao weighs? (accurate to 1 kg)
3. It is known that a factory has 70m and 52m fabrics. It is planned to produce 80 sets of A and B fashions with these two fabrics. It is known that the fabrics needed to make a set of A and B fashions are shown in the following table. Can the factory complete the task with existing raw materials? If yes, how many production plans are there? Please design it.
70 meters and 52 meters
A 0.6 m 0.9 m.
B 1. 1.4m
4. Transport a batch of goods by several cars with a load of seven tons. If each car only carries four tons, there is still 10 tons of goods left. If each car is full of seven tons, the last car will not be empty. Excuse me: How many cars are there?
It is known that Limin Garment Factory has 70m fabric A and 52m fabric B, and it is planned to produce 80 sets of M and N fashions with these two fabrics. It is known that making a set of M fashions requires 0.6 meters of fabric and 0.9 meters of fabric. To make an N-fashion, fabric A needs 1. 1 m, and fabric B needs 0.4m.. If the number of sets for producing N models is X, then there are several schemes for producing these two models with this batch of cloth.
6. Students A, B and C use their spare time to collect stamps. It is known that Party A has collected two more stamps than Party A, while Party C has collected four more stamps than Party A. The total amount collected by both parties is only six more stamps than Party C. How many stamps have they collected?
7. Design two schemes, measure the distance between two points AB on both sides of the river, and write the scheme without proof.
8. The students in Class Two, Grade One accepted the task of making flags. Originally, half of the students planned to make flags, 40 of which were made every day. One third of it was done, and the whole class did it together. As a result, it was finished one and a half days ahead of schedule. How many flags did * * * make?
9.AB is parallel to CD, and straight line EF intersects AB and CD at E and F respectively. If ∠FEB= 1 10 degrees ∠EFD = () a50b60c70d1/0ef is "/".
Best answer
Solution: There are X rooms and Y people.
There are 4x+20 = y... 1.
8x-8 & lt； y & lt8x......2
8x-8 < 4x+20 & lt； 8x
The solution is x = 6 and y = 44.
Answer: let Bao Xiao weigh x kilograms.
Then 2x+x
2x+x+6 & gt； Seventy two
22
So x=23.
Solution: Set a product X set and a product B set.
Then x+y=80.
0.6x+ 1. 1y & lt； =70
0.9x+0.4y & lt； =52
36
So x=36, 37, 38, 39, 40.
Therefore, tasks x=36 and y=44 can be completed; x=37，y = 43x=38，y = 42x=39，y = 4 1； x=40，y = 40
Solution: there are x cars and y tons of goods.
There are 4x+10 = y.
7x-7 & lt； y & lt7x
10/3 < = x & lt； = 17/3
So x = 4,5.
So there are four or five cars.
Solution: Set M Fashion X setting and N Fashion Y setting.
Then x+y=80.
0.6x+ 1. 1y & lt； =70
0.9x+0.4y & lt； =52
36
So x=36, 37, 38, 39, 40.
So x=36, y = 44x=37, y = 43x=38, y = 42x=39, y = 41; x=40，y = 40
Solution: Suppose A has X stamps, B has Y stamps and C has Z stamps.
In terms of meaning, X-Y = 2 (1) Z-X = 4 (2) X+Y-Z = 6 (3).
From ( 1): x=2+y (4)
Substituting (4) into (2) gives z-(2+y)=4 (5).
From (5): z=4+2+y (6)
Substituting (4) and (6) into (3) gives:
(2+y)+y-(4+2+y)=6
So y= 10
Substitute y= 10 into (4) to get x=2+ 10= 12.
Substitute y= 10 into (6) to get z=4+2+ 10= 16.
The solution of the equation: x =12 y =10 z =16.
A: A has 12 stamps, B has 10 stamps and C has 16 stamps.
Solution: Method 1:
Make an equal trapezoid with two points. Know the length and height of the base. You can calculate the distance between two points.
Method 2:
Use similar triangles.
Solution: Set ***x flag.
1/3x÷40+2/3x÷80 = x÷80+ 1
2x+2x=3x+240 (both sides are multiplied by 240)
x=240
Solution: AB is parallel to CD, and straight line EF intersects AB and CD at E and F respectively. If ∠FEB= 1 10 degrees ∠EFD is equal to (c) a50b60c70d110ef, because two straight lines are "/". ∠Fe b+∠EFD = 180∠EFD = 180-∠Fe b = 70
1. A project takes Party A 6 days to complete, and Party B alone 10 days. How many days does it take for Party A to do it alone?
Solution:
A's work efficiency =1/6-110 =115.
It takes1(115) =15 days to complete.
2. For a job, Party A will complete it in 5 hours 1, and Party B will complete half of the remaining tasks in 6 hours. Finally, Party A and Party B cooperated. How long will it take to finish the rest of the work?
Solution: A's work efficiency =( 1/4)/5= 1/20.
B completed (1-1/4) ×1/2 = 3/8.
Party B's work efficiency = (3/8)/6 =116.
The sum of the work efficiency of Party A and Party B =1/20+116 = 9/80.
At this point, 1- 1/4-3/8=3/8 has not been completed.
It takes (3/8)/(9/80)= 10/3 hours.
3. The construction team will complete a project in 30 days, with 18 people first and 12 days to complete 3/ 1 of the project. How many people will be added if it is completed on time?
Solution: Everyone's work efficiency = (1/3)/(12×18) =1/648.
It takes 30- 12= 18 days to finish on time.
Personnel required to finish the project on time (1-1/3)/(1/648×18) = 24 people.
Need to increase 24- 18=6 people.
4. Two people, Party A and Party B, process a batch of parts, with Party A processing 1.5 hours first, and then Party B processing. When the task is completed, Party A will complete five-eighths of this batch of parts. It is known that the efficiency ratio of Party A and Party B is 3:2. Q: How many hours does it take for Party A to process this batch of parts alone?
Solution: The working efficiency ratio of Party A and Party B is 3: 2.
That is, the ratio of workload is 3: 2.
B has completed 2/3 of A.
B Completed (1-5/8)=3/8.
Then when Party A and Party B work together, the amount of work completed is =(3/8)/(2/3)=9/ 16.
Therefore, it takes1.5/(5/8-9/16) =1.5/(1/6) = 24 hours.
5. A project needs the cooperation of Party A, Party B and Party C 13 days. If Party C has two days off, Party B will have to work four more days, or both parties will work 1 day. Q: How many days will it take for this project to be completed by Party A alone?
Solution: C for 2 days, B for 4 days.
In other words, it takes two days to do 1 day.
Then the workload of C 13 days is 2× 13=26 days.
Party B's 4 days is equivalent to 1 day.
That is, 3 days of B is equivalent to 1 day of A.
Armor alone takes a day to complete.
Then it takes three days for B to do it alone.
C it takes 3a/2 days for one person to do it.
According to the meaning of the question
1/a+ 1/3a+ 1/(3a/2)= 1/ 13
1/a( 1+ 1/3+2/3)= 1/ 13
1/a×2= 1/ 13
a=26
A It takes 26 days to do it alone.
Arithmetic: 13 days of C is equivalent to 26 days of B.
B doing 13+26=39 days is equivalent to A doing 39/3= 13 days.
So it takes a person 13+ 13=26 days to complete it.
6. Solution: Party B makes 60 sets, and Party A makes 60/(4/5)=75 sets.
A three days 165-75=90 sets.
A's work efficiency =90/3=30 sets.
B Processing 30×4/5=24 sets per day.
7. Party A and Party B produce a batch of parts. The efficiency ratio of Party A and Party B is 2: 1. Co-shoot for three days, and Party B will shoot alone for the other two days. At this time, Party A has produced 14 more parts than Party B. How many parts are there in this batch?
Solution: Take the work efficiency of B as the unit 1.
Then a's work efficiency is 2.
B 2 days to complete 1×2=2.
Otsuichi * * * produces 1×(3+2)=5.
A * * * Output 2×3=6
So the work efficiency B = 14/(6-5)= 14/ day.
A's work efficiency = 14×2 = 28/ day.
A * * * has 28×3+ 14×5= 154 parts.
Or let the work efficiency of Party A and Party B be 2a/ day and A/ day respectively.
2a×3-(3+2)a= 14
6a-5a= 14
a= 14
A * * * has 28×3+ 14×5= 154 parts.
1, A car and B car leave from AB at the same time. A walked 5/ 1 1 of the whole journey. If A drives at a speed of 4.5 kilometers per hour, B drives for 5 hours. How many kilometers are AB apart?
Solution: AB distance = (4.5× 5)/(5/11) = 49.5 km.
2. A bus and a truck leave from Party A and Party B at the same time. The speed of a truck is four-fifths that of a bus. After a quarter of the journey, the truck and the bus met for 28 kilometers. How many kilometers is it between A and B?
Solution: The speed ratio of passenger cars and trucks is 5: 4.
Then the distance ratio when meeting is 5: 4.
When they met, it was 4/9 of the whole truck journey.
At this time, the truck has traveled all the way 1/4.
4/9- 1/4=7/36 from the meeting point.
Then the whole journey = 28/(7/36) = 144km.
3. Party A and Party B walk around the city, with Party A walking 8 kilometers per hour and Party B walking 6 kilometers per hour. Now both of them start from the same place at the same time. After B meets A, it will take another 4 hours to return to the original starting point. B How long does it take to go around the city?
Solution: The speed ratio of A and B = 8: 6 = 4: 3.
When they met, B walked 3/7 of the way.
Then 4 hours is 4/7 of the whole trip.
Therefore, the time spent on line B in a week =4/(4/7)=7 hours.