1.

Teammates need to take the bus to Moon Mountain. The seat numbers of A, B, and C are three even numbers. The average number of seat numbers A and B is 11, the average number of seat numbers B and C is 13, and the undistinguished number of seat numbers A and C is 12. Please help them find their seats.

A is: B is: C is:

Answer: The average number of A and B is 11 A + B = 22

B, C The average number of seat numbers is 13, B + C = 26

The average number of seat numbers A and C is 12, A + C = 24

A is: 10, B is: 12, C Yes: 14

2.

Every two people share one rice bowl, every three people share one vegetable bowl, every four people share one soup bowl, and it costs 65 per day How many people are there in one bowl?

Answer: 65÷(1/2 + 1/3 + 1/4) = 60 people

3.

A ship is at A and B The boat travels back and forth at a speed of 30 kilometers per hour with the current and 20 kilometers per hour against the current. What is the average speed of this ship traveling back and forth between places A and B?

Answer: Solution; To find the average speed, it should be the total distance (round trip distance)/total time (total round trip time) = average speed

There is no need to set the distance between A and B as 1, because the total distance It can be approximated,

The total distance is twice the distance, it takes distance/30 hours to go downstream, and it takes distance/20 hours to go upstream,

So the average speed is

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2/(1/31/20)=2/((2+3)/60)=120/5=24 (km/h)

Answer: Average The speed is 24 kilometers per hour.

4.

The wall clock strikes 6 o'clock 6 times in 10 seconds. So if 9 o'clock is struck 9 times, how many seconds will it take to finish?

Answer: 6÷10=0.6

9÷0.6=15 (seconds)

Answer: Knock 9 times at 9 o'clock and finish in 15 seconds.

5.

There are 72 students in fifth grade and 66 students in sixth grade in a certain primary school. The school wants to organize students from both grades to participate in extracurricular activities and needs to be grouped according to grade. What is the maximum number of people in each group so that the number of people in each group is the same? At this time, how many groups were divided into the fifth grade and the sixth grade?

Answer: The greatest common divisor of 72 and 66 is 6

So there are at most 6 people in each group

The fifth grade is divided into 72÷6=12 groups< /p>

The sixth grade is divided into 66÷6=11 groups

6. The school bought three ropes to make skipping ropes. The lengths of the three ropes are 14m, 35m and 28m respectively. Now they need to be cut into A short rope of the same length with nothing left over. What is the longest length of the short rope? How many short ropes of this length can be cut?

Answer: The greatest common divisor of 14, 35 and 28 is 7

So the longest short rope cut into is 7 meters

It can be cut into (14＋35＋28 )÷7=11 roots

7.

A cuboid can be sawn into 5 small cubes. The sum of the surface areas of these 5 small cubes is 8 square centimeters larger than the surface area of ??the original cuboid. What is the surface area of ??this cuboid in square centimeters?

Answer: 22cm square

4 times 2 equals 8 sides

8 divided by 8 equals 1cm

A side is one centimeter long

1 times 5 times 4 plus 1 times 1 times 2 equals 22 centimeters

8. Fill a cube water tank with an edge length of 8 decimeters with water, and then pour the water into it. The bottom area is 80 What is the height of the water in a rectangular water tank measuring square decimeters?

Answer: 8*8*8/80=6.4dm

9. Put two cuboids with edges: 3 cm, length: 5 cm, width: 3 cm into one What is the area of ??a large rectangle?

Answer: (3*5+3*5+3*3)*2*2=156 (square centimeters)

10. A 30 cm long and 25 cm wide From a rectangular iron sheet, cut off a 5 cm square from each corner to make a rectangular iron box with a depth of 5 cm without a lid. What is the volume of this iron box in cubic centimeters? (The thickness of the iron sheet is not included)

Answer: 30-5*2=20 (cm)

25-5*2=15 (cm)

15 *20*5=1500 (square centimeters)

11. If the height of a cuboid is reduced by five centimeters, it becomes a cube. At this time, the surface area will be reduced by 120 square centimeters. The original volume of the cuboid How many cubic centimeters is it?

Answer: 120/4=30 (cm)

30/5=6 (cm)

5+6=11 (cm)

6*11*6=396 (cubic centimeters)

12. Two cars A and B drive opposite each other from A and B at the same time. Car A meets B on 9/17 of the whole journey. Cars meet. If car A travels 45 kilometers per hour. Car B completes the journey in 8 hours. What is the distance between the two places?

Answer: 1-9/17=8/17

8*8/17=64/17 hours

(45*64/17)/ (9/17) = 320 kilometers

13. A and B start from two places and travel opposite each other. It takes A 8 hours to complete the distance and B 6 hours to complete the distance. One hour and 30 minutes after setting off at the same time, B returns to the starting point and takes half an hour to pick up his things before setting off again. How many hours will pass after B sets off again and the two of them will meet? (The answer is expressed as a fraction)

Answer: Assume the total distance is 1, then the speeds of A and B are 1/8 and 1/6 respectively.

One hour and 30 minutes after the two set off at the same time, B returned to the starting point and took half an hour to pick up his things before setting off again, which means he set off 3.5 hours later than A. During this time, A has left (1/8)*3.5.

The sum of the speed of two people walking together is (1/8+1/6).

Then the time when the two meet should be:

(1-1/8*3.5)/(1/8+1/6)=27/14

14. Our class 48 people came. 54 people came from the second class. If the students in the two classes are divided into several groups, and the number of people in each group of the two classes is the same, how many people can be at most in each group?

Answer : 48＝2×2×2×2×3

54＝2×3×3×3

The greatest common divisor of 48 and 54 is 2×3＝6

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Maximum 6 people per group

15. The little girl said: "There are 150 people in the class of fifth grade, and there are 45 people with myopia.

The little boy said: "There are 45 people in class 5 (1), and there are 45 people with myopia. There are 10 people.

Question: How does the situation of students in Class 5 (1) wearing myopia eyes compare with the overall situation in fifth grade?

Answer:

The proportion of students in Class 5 (1) who wear myopia glasses is 10/45=2/9

The overall ratio in Class 5 is 45/150=3/10

So Class 5 (1) Compared with the overall situation of fifth grade students, the situation of students wearing glasses is better

The proportion of students wearing glasses is smaller

16. A and B are practicing a race. If A lets B run first 4 Seconds, then A can catch up with B by running for 10 seconds; if A asks B to run 10 meters first, then A can catch up with B by running for 6 seconds. What is the speed of A and B?

Answer: B’s speed x, A’s speed y

4x=10*(y-x)

10=6*(y-x)

Get

4x/10=10/6

x=25/6

y=175/12

17. There are 96.5 tons of grain in a warehouse. 36.8 tons were shipped out on the first day, and 23.9 tons were shipped in on the second day. How many tons of grain are there in the warehouse now?

Answer: 96.5-36.8+23.9=83.6 tons

18. In a long jump competition, Xiaoying jumped 3.78 meters, 0.5 meters closer than Yu Yu’s jump, and Yu Yu’s jump distance

0.39 meters away from Bi Xiaoming. How many meters did Xiao Ming jump?

Answer: 3.78+0.5-0.39=3.89 meters

19. An 8-meter-long bamboo pole is inserted into the pool. The part exposed above the water is 2.2 meters long and the part submerged in the mud is long

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0.65 meters, how many meters deep is the water in the pool?

Answer: 8-2.2-0.65=5.15 meters

20. Warehouse A originally contained 36.7 tons of wheat. After 5.3 tons were transported from warehouse B, the two warehouses stored < /p>

The weight of wheat is exactly the same. How many tons of wheat were originally stored in warehouse B?

Answer: 36.7+5.3+5.3=46.3 tons

21. There is a parallelogram glass plate with a base of 3.2 meters and a height of 1.5 meters. What is the area of ??this piece of glass in square meters? If the price of glass per square meter is 25 yuan, how much yuan does it cost to buy this piece of glass?

Answer: 3.2*1.5=4.8 square meters

4.8*25=120 yuan

22. Someone delivers goods from place A to place B. When he goes Traveling 204 meters per hour, it takes 3 hours to reach point B and 2 hours to return. What is the average speed of this person traveling back and forth? How many kilometers per hour?

Answer: The distance between A and B will not change. The total distance can be calculated based on the speed and time when you go there. If you have distance and time when you come back, can't you calculate the speed?

204*3/2=306

23. There are two vegetable fields, with a total income of 14,000 yuan, and an average income of 1,750 yuan per hectare.

It is known that the first vegetable field generates an income of 2,500 yuan per hectare, and the second vegetable field generates an income of 1,500 yuan per hectare. How many hectares are there in each of the two vegetable fields?

Answer: Because the ratio of the difference between the price of income per hectare of two vegetable fields and the average price of income per hectare is equal to the ratio of the areas of the two vegetable fields

(2500- 1750)÷(1750-1500)=3

14000÷1750÷(3+1)=2

So the areas of the two vegetable fields are 2 hectares and 6 hectares respectively

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24. In a row of telephone poles, the distance between two adjacent poles was originally 45 meters, but now it is 60 meters. If the starting pole does not move, how many meters later will another pole not move?

Answer: 180 meters! Find the lowest common multiple of 45 and 60.

25. I have a question, please help me: The school wants to buy 42 sets of tables and chairs. The price of each table is 55.5 yuan and the price of each chair is 24 yuan. How much does the school spend per day? Yuan?

Answer: (55.5+24)*42

26.

There is a batch of apples, each basket is 56 kilograms, which can hold 60 baskets. Now there are only 56 If you want to put all the apples in a basket, how many kilograms will be loaded in each basket on average?

Answer: 56 (kilograms) × 60 (baskets) ÷ 56 (baskets) = 60 (kilograms)

< p>27. A road construction team originally planned to build a road in 20 days. In fact, it built 45 meters more per day than the original plan, completing the task 5 days ahead of schedule. How many meters of road were originally planned to be built per day?

Answer: Completed 5 days ahead of schedule, that is, it took 20-5=15 days to build

An extra 45 meters was built every day, and 15×45=675 (meters) was built in 15 days

That is, the original 5 days were built Repair 675 meters, originally planned to repair 675÷5=135 (meters) every day

28. The elder sister and the younger sister are running on the circular track. The elder sister runs 212 meters per minute, and the younger sister runs 186 meters per minute, 16 minutes After the elder sister catches up with the younger sister for the first time, find the length of the runway

Answer:

The elder sister catches up with the younger sister for the first time, which means that the elder sister runs one more lap than the younger sister, which is the length of the runway. , so

It is 212*16-186*16=416 meters

29. There is a water box 150 cm long, 50 cm wide and 40 cm high, filled with water. , then put a rectangular stone with a height and length of 20 cm, and the water overflows 4 liters. How many centimeters is the width of the stone?

Answer: 4L=4000ML

150*50*4000=30000000 cubic centimeters

30000000/(20*20)=75000 centimeters

30. A certain kind of clothing is sold at a 30% discount, and the price after the price reduction is less than the original price 153 yuan, what is the original price of the clothing?

153/(1-0.3)=218.57

31. Places A and B are 480 kilometers apart. A truck traveling from A to B has traveled 1/6 of the entire distance. At that time, a passenger car drove from point B to point A. They met after 5 hours. It is known that the speed ratio of the passenger and freight cars is 7:9. Question: What is the speed of the passenger car?

Answer: 480*1/6=400 kilometers

400/5=80 kilometers

80÷7/16=35 kilometers

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32. A project takes 6 hours to complete by A alone, and 10 hours by B alone. If A; B, A; B. ． ． ． ．

Work alternately in sequence, one hour each time. How many hours will it take to complete?

Answer: Known: A completes 1/6 of the project per hour, while B completes 1/10

Then, A and B alternately complete 1/6+1/ every two hours 10

So if it takes X hours to complete

then there is (1/6+1/10)*X/2=1

X=7.5

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33. A classroom is 9 meters long, 6 meters wide, and 4 meters high. The area of ??doors, windows, and blackboards is 20 meters per square meter. Now it's time to paint the four walls and ceiling of this classroom.

A. How many square meters of area will be painted?

B. In the case of no loss, 0.5 liters of paint are required per square meter. If there is 1/9 loss in actual painting, how many liters of paint are needed per day?

Answer: A. How many square meters of area will be painted?

9*4*2+9*6+4*6*2=174 square meters

174-20=154 square meters

B. If there is no loss, 0.5 liters of paint are needed per square meter. If there is 1/9 loss in actual painting, how many liters of paint are needed per day?

174*0.5=87 liters

(87*1/9)+87=97 liters

34. A swimming pool is 20 meters long and 20 meters wide. It is 30 meters and 2 meters deep. Cement the bottom and walls of this swimming pool. According to experience, generally 2 coats are required. The first coat requires 0.6 kilograms of cement per square meter. The second coat requires 2/3 of the cement required for the first coat. How many kilograms of cement are needed per pound?

Answer: 20*3+2*3*2+20*2*2=152 kilograms

152*0.6=91.2 kilograms

(91.2* 2/3) + 91.2 = 152 kilograms

35. There are 90 table tennis balls in the sports supplies. If every two are put in a box, can it be filled exactly? If every five are put in a box, can it be filled exactly? Have you finished loading? Why?

90#2=45 boxes

90#5=18 boxes

Answer: If you pack one box for every two, can If you pack every five boxes, it will be just right. Because 90 is divisible by five.

36. There are 57 rubber balls in the sports store, and every three balls are packed in a box. Can they be packed completely?

57#3+19 boxes

Answer: It can be completely filled.

37. Two people, A and B, type a 10,000-word document. A types 115 words per minute and B types 135 words per minute. How many minutes does it take to finish typing?

10000# (115+135) = 40 points

Answer: You can finish the game in 40 minutes.

38. When fifth grade students plant trees, groups of 13 or 14 people are divided into groups. How many fifth grade students are there at least to participate in tree planting?

13X14=192 people

Answer: There are at least 192 people in fifth grade participating in tree planting.

39. Two cars are traveling in opposite directions from one place. One car travels 31 kilometers per hour, and the other car travels 31 kilometers per hour. Travel 44 kilometers. After how many minutes will the two cars be 300 kilometers apart?

Equation:

Solution: The two cars will meet after X time.

31X+ 44X=300

75X=300

X=4

4 hours = 240 minutes

Answer: Two cars after 240 minutes 300 kilometers apart.

40. Two engineering teams have to dig a 119-meter-long tunnel together. The two teams work from both ends. Team A digs 4 meters every day, and team B digs 4 meters every day. 3 meters, how many days will it take to dig the tunnel?

Solution: Suppose the tunnel is dug in X days

3X+4X=119

7X=119 < /p>

X=17

Answer: It took 17 days to dig the tunnel.

41. There are 140 people in the school chorus and dance team. The number of people is 6 times that of the dance team. How many people are there in the dance team?

Explanation: Suppose the dance team has X people

6X+X=140

7X= 140

X=20 people

Answer: There are 20 people in the dance team.

42. Two brothers go from home to the gymnasium at the same time. The road is 1300 meters long. The elder brother walked 80 meters per minute. The younger brother rode a bicycle at a speed of 180 meters per minute to the gymnasium and returned immediately. He met his elder brother on the way. How many minutes had the elder brother walked?

1300X2=2600 meters 2600#( 1880)

=2600#260

=10 points

Answer: My brother has been gone for 10 minutes.

43 .On Children’s Day, Teacher Wang bought 360 biscuits, 480 candies, and 400 fruits, and made exquisite small gift bags to give to the children as gifts. How many small gift bags can be made at most?

36 48400=1240 pieces

Answer: You can make up to 1240 small gift bags.

44. Naughty bought 40 balloons and invited classmates to come home to compete in blowing balloons. In order to be able to The balloons are divided equally. How many students should Naughty invite to compete in blowing balloons? Naughty will not participate.

40#2=20 people 40#4=10 people 40#5=8 people

40 #8=5 people 40#@0=4 people 40#20=2 people

Answer: There are 6 ways to invite classmates, namely: 20 people, 10 people, 5 people, 8 people, 4 people, 2 people.

45. A trapezoidal corn field, with an upper base of 15 meters, a lower base of 24 meters, and a height of 18 meters. On average, 9 corn plants are planted per square meter. This land is ** *How many corn plants can be planted?

(15+24)X18#2=351 square meters

351X9=3195 plants

Answer: This land can Plant 3159 corn plants.

46. The number of students in a certain class is less than 100. When lining up, there are exactly one more student in each row of 5, 4 and 3. How many students are there in this class?

5X4X3=60 people 61=61 people

Answer: There are 61 people in this class.

47. Wang Yue has a box of chocolate candies, 7 pieces each time. There are 5 candies, and 3 candies have 1 left. How many candies are there in this box of chocolates?

7X5X3=105 candies 105+1=106 candies

Answer: This box of chocolates There are at least 106 candies.

48. There is a rectangular corridor 15 meters long and 1.2 meters wide in Chenguang Community that needs to be paved with square tiles. The designer has prepared square tiles with a side length of 30 centimeters. Please do the math. Calculate: How many square bricks like this are needed? If each square brick is 3 yuan, how much yuan does it cost to pave this corridor?

15 meters = 150 decimeters 1.2 meters = 12 decimeters 30 centimeters = 3 decimeters

150X12=1

800 square decimeters 3X3=9 square decimeters

1800#9=200 blocks 200X3=600 yuan

Answer: You need 200 square bricks like this, which cost 600 yuan.

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50. There are two parallelogram experimental fields with equal areas. One has a base length of 70 meters and a height of 45 meters, and the other has a base length of 90 meters. How many meters is the height?

70X45 =3150 square meters 3150#90=35 meters

Answer: The height is 35 meters.

51. A batch of steel pipes are stacked in a pile, with 10 on the bottom layer and one layer on each upper layer. Put 1 less steel pipe, and put 5 steel pipes on the top layer. How many steel pipes are there in this batch?

10-5+1=6 layers (15)X6#2

=15X6#2

=90#2

=45 pieces

Answer: There are 45 steel pipes in this batch.

52. The elder brother and younger brother *** have 100 pages of manuscript paper. If the elder brother gives his younger brother 20 sheets of manuscript paper, they both have the same number of manuscript pages. How many pages of manuscript paper did the elder brother and the younger brother have each?

Answer: Suppose the elder brother has >

Calculate X=60, Y=40

53. The school bought back 1 computer and 2 computer desks, costing 6750 yuan per ***. It is known that the price of each computer is 6 times that of the computer desk. What is the unit price of the computer and the computer desk?

Answer: Suppose each computer costs X yuan and each computer desk costs Y yuan

Set of equations [X+2Y=6750

[ X=6Y < /p>

Calculate If we add another 20 people, the number of fifth graders will be 1/2 of the sixth graders. How many people in fifth grade and sixth grade originally volunteered to participate in the activities?

Answer: Suppose there are [X=1/2(Y+20)

Calculate X=60, Y=100

55. A bookshelf, the upper floor has 105 more books than the lower floor, take 25 books from the upper floor After placing it on the lower level, the books on the lower level are 4 and 5 on the upper level. How many books are originally on the upper level of the bookshelf?

Answer: Let the upper book be X and the lower book be Y,

X-Y=105

[X-25]*[4/5]=Y +25

The distance between the cars is 568 kilometers. It is known that a truck travels 8 kilometers per hour faster than a passenger car. How many kilometers does the bus travel per hour?

Suppose the passenger car is Riding a motorcycle, starting from two places 60 kilometers apart and heading towards each other at the same time. After meeting on the way, keep going and turn your back. Six hours after departure, they were 240 kilometers apart. It is known that Li Xin travels 18 kilometers per hour. How many kilometers does Liu Qiang travel per hour?

6 (18 + are running towards each other at the same time. At the same time, the puppy brought by A is running towards B at a speed of 7.5 kilometers/hour. The puppy immediately turns back and runs towards A after meeting B. After meeting A, it runs towards B again... until A, B The two met and asked for the distance traveled by the puppy.

Because the time for the puppy to walk = the time for A and B to walk

So the distance of the puppy = the time of the puppy * the speed of the puppy

= A and B's Time*Puppy’s speed

=22.5/(2.5+5)*7.5

=22.5 (kilometer)

59, a certain aircraft was originally scheduled to Flying to the destination at a speed of 495 kilometers per hour, due to an urgent mission, the flight speed was increased to 660 kilometers per hour. As a result, we arrived one hour early. How many kilometers is the total distance?

x/495-x/660=1

60. First eat 0.6 kilograms of soy sauce in the bottle, and then eat the remaining 3/5. There is still 0.8 kilograms of soy sauce in the bottle. . How many kilograms does this bottle of soy sauce originally weigh?

(X-0.6)*(1-3/5)=0.8