Three people * * *: 18+20+ 16 = 54 (years old)
A: 54-20×2= 14 (years old)
B: 54- 16×2=22 (years old)
C: 54- 18×2= 18 (years old)
2) Party A and Party B cooperate to produce 165 parts in 3 hours. If they work 8 hours respectively, Party A will produce 40 more parts than Party B. How many parts will Party A and Party B produce per hour?
Answer: (165÷3+40)÷8 ÷2=30 (pieces)
B: 165÷3-30=25 (pieces)
3) The original warehouses A and B have 350 tons of grain. If 9 1 ton is shipped from warehouse A and 80 tons is shipped from warehouse B, the inventory of warehouse B is 6 tons more than that of warehouse A. How many tons are there in warehouses A and B?
A original: (350-91+80-6) ÷ (1+1/2)+91= 313 (ton)
B original: 350-3 13=37 (ton)
4) The bus and truck run in opposite directions from two stations A and B respectively at the same time. It takes 3 hours for the bus to complete the journey. The speed of the truck is 60 kilometers per hour, and it will meet the bus after 72 kilometers. How many kilometers is it between Station A and bilibili?
72 ÷ (1-72 ÷ 60 ÷ 3) =120 (km)
5) A class held a parent-teacher meeting and prepared teacups for each parent. As a result, five cups were missing. Later, I borrowed half the cup. There are 13 cups at this time. How many parents attended the meeting?
(5+13) ÷1/2+5 = 41(person)
6) The machine tool factory used to know that each machine tool used steel 1.02 tons. After the improved design, each machine tool saves 0.65,438+0.2 tons compared with the original machine tool. How many machine tools can we make now?
1.02-0.12 =1(ton)
300× 1.02=306 (ton)
306 ÷ 1 = 306 (Taiwan Province)
7) Xiaoming bought six pencils and four exercise books at 0.68 yuan each and 0.24 yuan each. Xiao Ming paid 5 yuan money, how much should he get back?
0.68×4=2.72 (yuan)
0.24× 6 = 1.44 (yuan)
2.72+ 1.44=4. 16 (yuan)
5-4. 16=0.84 (yuan)
8) Two trains, A and B, leave from two places at the same time. The speed of train A is 80 kilometers per hour, and that of train B is 70 kilometers per hour. After 12 hours, the distance between the two trains is still 1 10km. What is the distance between the two places?
(80+70)× 12= 1800 (km)
1800+110 =1910 (km)
9) Guangming Paper Mill produced a batch of newsprint, which was originally planned to be completed in 28 days, with a daily output of 12.5 tons. Now it's finished three days ahead of schedule. How many tons are actually produced every day than originally planned?
28× 12.5 = 350 (ton)
28 3 = 25 days
350÷25= 14 (ton)
14-12.5 =1.5 (ton)
10) Li Shifu has produced a batch of parts. Three days ago, 126 parts were produced. According to this calculation, it takes 12 days to complete the production task. How many parts are there in this batch?
126 ÷ 3 = 42 (pieces)
42× (12+3) = 630 (pieces)
1 1) The fertilizer plant planned to produce 84 tons of fertilizer in 30 days, but actually produced 0.2 tons more than planned every day. How many days did it actually finish the task ahead of schedule?
84÷30=2.8 (ton)
2.8+0.2=3 (ton)
84÷3=28 (days)
30-28=2 (days)
12) processing a batch of clothes, processing 300 sets a day, 16 days can be completed.
(1) If 400 sets are processed every day, how many days will it be completed in advance?
300× 16 = 4800 (set)
4800 ÷ 400 = 12 (days)
16- 12=4 (days)
(2) If 20 sets are processed every day, how many days can it be completed?
300+20=320 (set)
4800÷320= 15 (days)
(3) If it is to be completed five days in advance, how many sets will be processed every day?
16-5= 1 1 (days)
4800÷ 1 1 is about equal to 436 (sets).
13) A car factory plans to produce 16800 cars throughout the year. Results The annual production task was completed two months ahead of schedule. At this rate, how many cars can be produced throughout the year?
16800÷ (10-2) =1680 sets.
1680×12 = 20160 sets.
14) A workshop of Xinfeng Agricultural Machinery Factory processes 2480 parts. Originally, 100 pieces were processed every day, and after working for 20 days, 120 pieces were processed every day. So we can finish the task in a few days.
100× 20 = 2000
2480-2000 = 480
480 ÷ 120 = 4 days
15) A garment factory used to make a children's garment, and the cloth was 2.2 meters at a time. Now the cutting method has been improved, and each set saves 0.2 meters of cloth. The cloth used to make 600 sets of this kind of clothes, how many sets can be made now?
600× 2.2 =1320m
2.2-0.2 = 2m
1320 ÷ 2 = 660 sets
16) has a cube with a length of 70cm, a width of 50cm and a height of 45cm. What is the maximum volume of these cubes if they are to be cut into cubes of the same size?
70=2×5×7
50=2×5×5
45=3×3×5
The greatest common factor of 70, 50 and 45 is 5.
Therefore, the side length of the small cube is 5 cm.
The maximum volume of these cubes is 5× 5× 5 = 125 (cubic centimeter
17) The distance between A and B is 465km. A car drove from A to B, and after driving at a speed of 60km for a period of time, it accelerated to 15km/h, and it took * * * 7 hours to reach B. How many hours have you been driving at a speed of 60 km per hour?
Solution: Suppose it travels at 60 kilometers per hour for x hours.
60x+(60+ 15)(7-x)=465
60x+525-75x=465
525- 15x=465
15x=60
x=4
A: I drove at 60 kilometers per hour for four hours.
18) There are several chickens and rabbits in the cage, which are *** 100 feet. If the chicken is replaced by a rabbit and the rabbit is replaced by a chicken, it has 92 feet. How many rabbits and chickens are there in the cage?
Solution: When rabbits are replaced by chickens, each rabbit loses two feet.
( 100-92)/2=4,
There are four rabbits.
(100-4*4)/2=42 pieces.
A: There are 4 rabbits and 42 chickens.
Spiders have eight legs, dragonflies have six legs and two pairs of wings. Cicada has six legs, 1 pair of wings. At present, there are 18 of these three kinds of bugs, with 1 18 legs and 20 pairs of wings. How many bugs are there in each species?
Solution: Set 18 Spider, Y Dragonfly and Z Cicada.
Three bugs * * *18, get:
X+y+z = 18 ... one type.
There are 1 18 legs, so:
8x+6y+6z = 1 18 ...
With 20 pairs of wings, you must:
2y+z = 20...c type
Where b -6*a gives:
8x+6y+6z-6(x+y+z)= 1 18-6 * 18
2x= 10
x=5
There are five spiders,
Then 18-5= 13 dragonflies and cicadas.
Then change z to (13-y).
Substitute it into type C, and you get:
2y+ 13-y=20
y=7
There are seven dragonflies.
There are 65438 cicadas +08-5-7 = 6 cicadas.
There are five spiders, seven dragonflies and six cicadas.
20) In the activity of learning from Lei Feng, students * * * did 240 good deeds, the older students each did 8 good deeds, and the younger students each did 3 good deeds, with an average of 6 good deeds. How many students are there in this activity?
Solution: The students did 240 good deeds, with an average of 6 good deeds per person.
That means there are 240/6=40 of them.
There are x students in Datong University and (40-x) students in primary school.
8x+3(40-x)=240
8x+ 120-3x=240
5x+ 120=240
5x= 120
x=24
40-x= 16
A: There are 24 students in Datong University and 0/6 students in primary school/KLOC.
2 1) Forty-two students in a class participated in tree planting, with an average of 3 trees planted by boys and 2 trees planted by girls. It is understood that boys plant 56 more trees than girls. How many boys and girls are there?
Solution: There are X boys and 42-x girls.
3x-2(42 x)= 56
3x+2x-84=56
5x= 140
x=28
42-x= 14
A: Boys are 28 and girls are 14.
22) The clerk changed a 5 yuan RMB and a 50-cent RMB into 28 RMB with face value of 1 yuan and 1 minute. How much RMB do you want in return?
Solution: x sheets of 1 element and (28-x) sheets of 1 angle.
x+0. 1(28-x)=5.5
0.9x=2.7
x=3
28-x=25
A: There are three Zhang Yiyuan bills and 25 dimes.
23) RMB * * 50, with a total face value of 1 16 yuan. As we all know, one yuan is more than two yuan. How many RMB are there in three denominations?
Solution: Let 1 element have X, 2 yuan (x-2) and 5 yuan (52-2x).
x+2(x-2)+5(52-2x)= 1 16
x+2x-4+260- 10x = 1 16
7x= 140
x=20
x-2= 18
52-2x= 12
A: There are 20 1 yuan, 8 18 in 2 yuan and 2 12 in 5 yuan.
24) 400 movie tickets from 3 yuan, 5 yuan and 7 yuan, with a value of 1920 yuan, among which 7 yuan and 5 yuan have equal tickets. How many movie tickets are there for each of the three prices?
Solution: There are X pieces in 5 yuan, 7 yuan and (400-2x) pieces in 3 yuan.
7x+5x+3(400-2x)= 1920
12x+ 1200-6x = 1920
6x=720
x= 120
400-2x= 160
A: 3 yuan has 160 and 7 yuan and 5 yuan have 120.
Two kinds of cars are used to transport goods. Each car contains 18 boxes, and each car contains 12 boxes. Now there is a 18 car, worth 3024 yuan. If each box is cheap in 2 yuan, then the goods are worth 2520 yuan. Q: How many cars are there?
Answer: Total cargo: (3024-2520)÷2=252 (boxes)
There are x buses and (18-x) cars.
18x+ 12( 18-x)= 252
18x+2 16- 12x = 252
6x=36
x=6
18-x= 12
Answer: Bus No.6, 12.
26) A truck can transport ore 20 times a day in sunny days and 12 times a day in rainy days. Transportation 1 12 times a day, with an average of 14 times a day. How many days are it rainy these days?
Solution: Days = 1 12÷ 14=8 days.
It rained on day X.
20(8-x)+ 12x = 1 12
160-20x+ 12x = 1 12
8x=48
x=6
There are six rainy days.
27) Shipped a batch of watermelons, ready to be sold in two categories, big 0.4 yuan and small 0.3 yuan, so selling these watermelons is worth 290 yuan. If the price per kilogram of watermelons is reduced by 0.05 yuan, these watermelons can only be sold in 250 yuan. Q: How many kilograms is the watermelon?
Solution: Watermelon number: (290-250)÷0.05=800 kg.
There is a big watermelon x kg.
0.4x+0.3(800-x)=290
0.4x+240-0.3x=290
0. 1x=50
x=500
There are 500 kilograms of big watermelons.
28) In the darts competition, Party A and Party B are required to score 65,438+00 points for each win and deduct 6 points for each miss. Each person throws 10 times, and * * gets 152 points, among which Party A has more 16 points than Party B. Q: How many times did they win each time?
Solution: A score: (152+ 16)÷2=84.
B: 152-84=68 points.
Set armor x times
10x-6( 10-x)=84
10x-60+6x=84
16x= 144
x=9
Set b to y times.
10y-6( 10-y)=68
16y= 128
y=8
A: Nine times for A and eight times for B. ..
29) There are 20 questions in the math contest, and he gets 5 points for each correct answer. If he answers a wrong question, he will not only get no points, but also deduct 2 points backwards. Xiaoming got 86 points in this competition. Q: How many questions did he answer correctly?
Solution: Suppose he answered question X correctly.
5x-2(20-x)=86
5x-40+2x=86
7x= 126
x= 18
A: He got it right 18.
30)/building kloc-0/three households, with a one-time deposit of 2,700 yuan. The Li family saves less 250 yuan than the Wang family, and the Wang family saves more 80 yuan than the Zhang family. How much does each of them save?
Solution: Suppose the Wangs deposit X yuan, the Lijias deposit x-250, and the Zhangjias deposit x-80 yuan.
x+(x-250)+(x-80)=2700
3x-330=2700
3x=2700+330
3x=3030
x= 10 10
x-250=760
x-80=930
A: Wang's deposit 10 10 yuan, Li's deposit in 760 yuan and Zhang's deposit in 930 yuan.
3 1) A cage can hold 18 rabbits and 9 chickens of the same size, or 14 rabbits and 15 chickens of the same size. If it is specially used as a rabbit cage, how many rabbits can it hold at most?
Solution: Let the cage be M, a rabbit occupy space X and a chicken occupy space Y. 。
m= 18x+9y
m= 14x+ 15y
Available:18x+9y =14x+15y.
4x=6y
2x=3y
y=2/3x
So: m= 18x+9*2/3x.
m= 18x+6x
m=24x
A: It can accommodate up to 24 rabbits.
32) Party A, Party B and Party C. Party A is three years older than Party B and Party B is two years younger than Party C. The sum of their ages is 109. How old are they?
Solution: Let the age of B be X, the age of A be 2x+3, and the age of C be (x+2)/2.
x+2x+3+(x+2)/2= 109
3x+ 1/2x+4= 109
7/2x= 105
7x=2 10
x=30
2x+3=63
(x+2)/2= 16
A: A is 63 years old, B is 30 years old, and C 16 years old.
33) Young Pioneers 123 Squadron * * * killed 200 rats, and the number of rats killed by the second squadron was twice that of the first squadron. The third squadron is equipped with a squadron to fight X rats, the second squadron to fight 2x+5 rats +5 rats, and the third squadron to fight 3x+9 rats +9 rats.
Note: x+2x+5+4=3x+9!
x+2x+5+3x+9=200
6x+ 14=200
6x= 186
x=3 1
2x+5=67
3x+9= 102
Answer: The first squadron killed 3 1 mouse, the second squadron killed 67 mice, and the third squadron killed 102 mice. The number of rats killed is four more than the sum of the first and second squadrons. How many rats did each of the three squadrons kill?
34) Party A travels 12km per hour, and Party B travels 8km per hour. One day, A went from East Village to West Village, and B went from West Village to East Village at the same time. It is known that when B arrived in the East Village, A had arrived in the West Village for five hours. Find out the distance between the two villages. ..
Assuming that the walking time of A is X, then
12 * X = 8 * (X+5) calculated X = 10.
Then the distance between the two villages is 12 * 10 = 120 (unit).
35) A ship travels 75 kilometers per hour from A to B and 50 kilometers per hour when it comes back. Find the average speed of the ship.
It took x hours to set it up.
Average speed = total length/total time So: total length is 75 * X * 2 = 150 X (round trip).
The total time is x+75x/50 = 2.5x..
So the average speed is 150 X/2.5 X = 60 (unit
36) Zhou Yan Liu Min and Zhang Xin each have some stickers. After Zhou Yan gave Liu Min 13 and Liu Min gave Zhang Xin 15, the number of stickers of the three people was the same. It turns out that Liu Min has more than Zhang Xin?
Let Zhou Yan have X, then Liu Min has X- 13+ 15 = X+2, and then a new one has X- 13- 15 = X-28.
Then the difference between two people is X-X+28 = 28.
37) Party A deposits in 520 yuan and Party B deposits in 240 yuan. After they withdraw the same money, Party A's remaining money is five times that of Party B. How much do you want them to withdraw?
Let's assume x yuan.
520-X = (240-X) * 5 results X = 170 yuan.
38) Two cars, A and B, are driving in the same direction from location A at the same time. Car A is 6 kilometers faster than car B every hour, and car A arrives at place B 45 minutes earlier. When car B arrives at place B, car A travels to place C, which is 36 kilometers away from place B, and it is () kilometers from place A to place C.
Solution: According to the meaning of the question, A-C * * takes 36÷6=6 hours and the speed is 36 ÷ 3/4 = 48 km/h.
So the formula: 48×6=288 (km)
39) Yang Ping walks from home to school on time every day, and Uncle Li goes out for a walk regularly every morning. They walk in opposite directions. Yang Ping walks 80 meters per minute, and Uncle Li walks 70 meters per minute. They meet on time on the road every day. One day, Yang Ping went out early, so he saw Uncle Li at 8 o'clock earlier than usual, so Yang Ping went out earlier than usual.
Solution: According to the meaning of the question, Yang Ping will leave 8 minutes early, so the formula is: (80+70)×8÷80= 15 (minutes).
40) Two cars, A and B, start from A and bilibili at the same time, and drive along the expressway in opposite directions. It is known that the speed of car A is 1.5 times that of car B, and the time when car A and car B arrive at station C is 5: 00 and 16:00 respectively, and the time when they meet is ().
Solution: (omitted) As can be seen from the meaning of the question, A to point C and B to point D meet at point E, and B follows.
D to C needs 1 1 hour, and the distance ratio of Ce: ED is 3: 2, so the formula is:
5+ 1 1×2/5=9: 24
4 1) A walks from place A to place B, and B rides a bike from place B to place A. 1, they meet on the road. After arriving at A, B immediately returned to B and caught up with A 40 minutes after the first meeting. From b to b and back to a. Then B catches up with A () and meets A again.
Solution: According to the meaning of the question, Party A and Party B walk the whole journey from A to B at 1 hour. Then when we met for the third time, * * * walked three full distances, so 60×3-60-40=80 (minutes).
[Divide by # instead of multiplying by X ..
42) There are 90 ping-pong balls in the sporting goods. If every two are packed in a box, can they be packed properly? If you pack a box every five, can you finish it? Why?
90÷ 2=45 boxes 90÷ 5= 18 boxes
A: If every two are packed in a box, they can be packed accurately. If every five are packed in a box, it can also be packed accurately. Because 90 is divisible by 5.
There are 57 balls in the sporting goods store. Every three balls are packed in a box. Can they be properly packed?
57÷ 3+ 19 box
A: I can just finish it.
44) Party A and Party B type a document of 10000 words, with Party A typing 1 15 words per minute and Party B typing 135 words per minute. How many minutes will it take?
10000 (115+135) = 40 points.
A: It will be completed in 40 minutes.
45) The fifth-grade students planted trees, 13 or 14 each group just finished. How many students took part in planting trees in grade five?
13x14 =192 people
Answer: At least 192 people participated in tree planting in the fifth grade.
Two cars are driving in opposite directions from one place. One car has a speed of 365,438+0 kilometers per hour, and the other car has a speed of 44 kilometers per hour. How many minutes later, the distance between the two cars is 300 kilometers?
Equation:
Solution: Two cars meet after X point.
3 1X+44X=300
75X=300
X=4 4 hours =240 minutes
Answer: After 240 minutes, the distance between the two cars is 300 kilometers.
47) Two construction teams will * * * excavate a tunnel with a length of 1 19 meters, and the two construction teams will construct from both ends respectively. Team A digs 4 meters every day, while Team B digs 3 meters every day. How many days does it take to dig the tunnel?
Solution: Set X days to dig tunnels.
3X+4X= 1 19
7X= 1 19
X= 17
Answer: 17 days, the tunnel was dug.
48) School chorus and dance team 140 people. There are six times as many people in the chorus as in the dance team. How many people are there in the dance team?
Solution: There are X people in the dance team.
6X+X= 140
7X= 140
X=20 people
A: There are 20 people in the dance team.
49) The two brothers walked from home to the gym at the same time, with a length of 1300m. My brother walks 80 meters every minute, and my brother rides his bike to the gym at a speed of180 meters per minute, and then comes back immediately. On the way, he met his brother. How many minutes did my brother walk?
1300× 2=2600 m2600 (180+80)
=2600÷ 260
= 10 point
Answer: At this time, my brother left 10 minutes.
50) On Children's Day, Mr. Wang bought 360 biscuits, 480 sweets and 400 fruits, made a beautiful gift package and distributed it to the children as gifts. How many gift packages can he make at most?
360+480+400= 1240
Answer: You can make at most 1240 small gift packages.
5 1) naughty bought 40 balloons and invited students to blow them at home. In order to share the balloons equally, how many students should be invited to blow them? Naughty not to 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
A: There are six ways to invite students, namely: 20, 10, 5, 8, 4 and 2.
52) Trapezoidal cornfield, with the upper bottom15m, the lower bottom 24m and the height18m. There are 9 corn plants per square meter on average. How many corn can be planted in this field?
( 15+24)× 18÷2 = 35 1 m2
35 1× 9=3 195 strain
A: This land can grow 3 159 maize plants.
53) The number of students in a class is less than 100. When waiting in line, there is just one more person in each row, five, four and three. How many people are there in this class?
5× 4× 3=60 people 60+ 1=6 1 person
A: There are 6 1 person in this class.
54) Wang Yue has a box of chocolate candy, and the number of 7, 5 and 3 chocolates at a time is above 1. How many chocolates are there in this box?
7× 5× 3= 105 capsules 105+ 1= 106 capsules.
There are at least 106 chocolates in this box.
55) There is a rectangular tunnel with a length of 15m and a width of 1.2m in Chenguang Community, which needs to be paved with square bricks. The designer prepared a square brick with a side length of 30cm. Please calculate: how many such bricks are needed? If each square brick is 3 yuan, how much will it cost to build this tunnel?
15m = 150 decimeter 1.2m = 12 decimeter 30cm =3 decimeter.
150×12 =1800 square decimeter 3× 3=9 square decimeter.
1800÷ 9=200 pieces 200× 3=600 yuan.
Answer: We need 200 such square bricks, and we need 600 yuan.
56) There are two parallelogram experimental fields with equal area. One is 70 meters long and 45 meters high, and the other is 90 meters long and how many meters high?
70×45 = 3 150 m2 3 150 # 90 = 35m
A: The height is 35 meters.
57) A batch of steel pipes shall be stacked in a pile, with the bottom layer 10, each top layer 1 less, and the top layer 1 less, with 5 pieces. How many steel pipes are there in this batch?
10-5+ 1=6 floors (10+5)× 6÷ 2
= 15× 6÷ 2
=90÷ 2
=45 pieces
A: There are 45 steel pipes in this batch.
58) Saw a rectangular piece of wood with the length, width and height of 90cm, 30cm and 15cm into cubes with the same size, without any redundancy. What is the longest side of the sawed cube? How many such cubes can you see?
Because it is the longest and has no remainder, the greatest common factor of 90, 30, 15 should be taken as the side length. Their greatest common factor is 15, and the longest side length of a cube is 15 cm.
The number of sawable cubes is: (90/15) × (30/15 )× (15/15) = 6 * 2 *1=12 (.
60) Repair 0.25KM per day in the first 5 days and 2.65KM in the last 8 days. How many kilometers are repaired on average every day?
(5*0.25+2.65)/(5+8)
=( 1.25+2.65)/ 13
=3.9/ 13
=0.3
The average daily repair is 0.3KM.
6 1) Xiaoming and his father go to the park to play. When they bought tickets, his father paid 20 yuan and got 3.5 yuan back. If the price of student tickets in the park is half that of adult tickets, how much are the student tickets and adult tickets?
A * * * spent 20-3.5= 16.5 yuan.
Because student tickets are half the price of adult tickets.
So one adult ticket can buy two student tickets.
So 16.5 * * can buy three student tickets.
So the price of student tickets is 5.5 yuan.
So the fare for an adult is 1 1 yuan.
62) It is known that basketball, football and volleyball spend an average of 10 yuan per 36 yuan, and football spends more than volleyball. How much is each football?
Solution: Let each football be X yuan.
(X-8)+(X-8+ 10)+X=36*3
3X-6= 108
3X= 1 14
X=38
Every football 38 yuan.