1) The average age of A and B is 18 years old, the average age of B and C is 20 years old, and the average age of A and C is 16 years old. How old are A, B, and C?
.Three people ***: 18+216=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) A and B cooperate, 3 hours* **Produces 165 parts. If they work 8 hours each, then A can produce 40 more parts than B. How many parts can A and B make per hour?
A: (165÷3+40)÷8 ÷2=30 (pieces)
B: 165÷3-30=25 (pieces)
3) There are 350 tons of grain in the two original warehouses A and B. If 91 tons are shipped out from warehouse A and 80 tons are transported in from warehouse B, then the stock in warehouse B is 6 tons more than half of warehouse A. It turns out that how many tons are there in warehouse A and warehouse B?
Original A: (350-91+80-6)÷(1+1/2)+91=313 (tons)
Original B: 350-313=37 (tons)
4) Passenger cars and trucks travel towards each other from station A and station B at the same time. It takes 3 hours for the passenger car to complete the journey. The truck travels 60 kilometers per hour, and it travels 72 kilometers with the passenger car. meet. How many kilometers are there between stations A and B?
72÷(1-72÷60÷3)=120 (kilometers)
5) A certain class held a parent-teacher meeting and prepared a tea cup for each parent, but the result was less 5, and later I borrowed only half of the cups. Then there were 13 more teacups. How many parents were present at the meeting this time?
.(5+13)÷1/2+5=41 (people)
6) The machine tool factory originally knew that each machine tool uses 1.02 tons of steel. After improving the design, each The machine tool saves 0.12 tons compared with the original. The steel used to manufacture 300 machines was originally used. How many more machine tools can now be manufactured?
1.02-0.12=1 (ton)
300×1.02=306 (ton)
306÷1=306 (unit)
< p>7) Xiao Ming bought 6 pencils and 4 exercise books, each exercise book costs 0.68 yuan and each pencil costs 0.24 yuan. Xiao Ming pays 5 yuan, how much money should he get back?0.68×4=2.72 (yuan)
0.24×6=1.44 (yuan)
2.72+1.44=4.16 (yuan)
< p>5-4.16=0.84 (yuan)8) Two trains A and B leave from two places opposite each other at the same time. Train A travels 80 kilometers per hour, and train B travels 70 kilometers per hour. , 12 hours after driving, the two cars are still 110 kilometers apart. How many kilometers are there between the two places?
(870)×12=1800 (km)
180110=1910 (km)
9) Guangming Paper Factory produces a batch of newsprint , originally planned to be completed in 28 days, requiring a daily production of 12.5 tons. It is now completed 3 days ahead of schedule. How many more tons are actually produced per day than originally planned?
28×12.5=350 (tons)
28-3=25 (days)
350÷25=14 (tons)
< p>14-12.5=1.5 (tons)10) Master Li produces a batch of parts. In the first three days, he produced 126 parts. According to this calculation, it will take another 12 days to complete the production task.
How many parts are there in this batch?
126÷3＝42 (pieces)
42×(12+3)＝630 (pieces)
11) The fertilizer factory plans to produce in 30 days There are 84 tons of chemical fertilizers. The actual production is 0.2 tons more than planned every day. How many days earlier than planned is the task completed?
84÷30=2.8 (tons)
2.8+0.2=3 (tons)
84÷3=28 (days)
< p>30-28=2 (days)12) Processing a batch of clothing, 300 sets per day, can be completed in 16 days,
(1) If 400 sets are processed per day, How many days in advance will it be completed?
300×16＝4800 (set)
4800÷400＝12 (days)
16-12=4 (days)
< p>(2) If we process 20 more sets every day, how many days will it take to complete the process?3020=320 (sets)
4800÷320=15 (days)
(3) If it needs to be completed 5 days in advance, it must be processed every day How many sets?
16-5=11 (days)
4800÷11 is approximately equal to 436 (sets)
13) A certain automobile factory plans to produce 16,800 cars throughout the year , as a result, the entire year's production tasks were completed 2 months ahead of schedule. At this rate, how many cars can be produced throughout the year?
16800÷(10-2)=1680 units
1680×12=20160 units
14) A workshop of Xinfeng Agricultural Machinery Factory processes 2480 parts. It used to be 100 pieces per day, but after 20 days of work, it was changed to 120 pieces per day. How many more days of processing will it take to complete the task?
100×20=2000 pieces
2480-2000=480 pieces
480÷120=4 days
15) One garment The factory originally made a kind of children's clothing, and each set used 2.2 meters of cloth. Now the cutting method has been improved, saving 0.2 meters of cloth per set. The cloth used to make 600 sets of this kind of clothing, how many sets can now be made?
600×2.2=1320 meters
2.2-0.2=2 meters
1320÷2=660 sets
16) There is one Cube, 70 cm long, 50 cm wide, 45 cm high. If you want to cut it into cubes of the same size, what is the maximum volume in cubic centimeters of these small cubes?
70＝2×5×7
50＝2×5×5
45＝3×3×5
70 , the greatest common factor of 50 and 45 is 5
So, the edge length of the small cube is 5 cm
The maximum volume of these small cubes is 5×5×5=125 (cubic Centimeters
17) Cut 1/4 of a rope, which is exactly 14.4 meters. What is the length of the rope?
Rope length: 14.4÷1/4=57.6 meters
18) The school carries out tree planting activities. The number of trees planted in grade 6 is 39. The number of trees planted in grade 5 is 12/13 of the number in grade 6. The number of trees planted in grade 4 is 5/64 of grade 5. How many trees are planted in grade 5?
Tree planting in Grade 4: 39×12/13×5/6=30 trees
19) A batch of coal transported away his 1/5, which is exactly 1/6 tons, Find the total amount of coal in this batch.
1/6÷(1-1/5)=5/24 tons
20) A bank originally planned to issue 50 million yuan in treasury bills in 20 days, but it was completed in the first 6 days 2/5 of the plan, based on this calculation, how many days in advance can the task be completed?
Originally planned to complete 2/5: 20*2/5=8 days
Now to complete 2/5: 8-6=2 days
It now takes: 2÷2/5=5 days
The task can be completed in advance: 20-5=15 days
21) Subtract 1/5 from 1 rope, and After connecting 5 meters, it is 3/20 shorter than before. How many meters is the rope now?
x-1/5x+5=17/20x
4/5x+5=17/20x
5=1/20x
x=100
Then the rope is now 17/20*100=85 meters
22) A batch of coal transported away his 1/5 which is exactly 1/6 tons, find the total quantity of this batch of coal.
A bank originally planned to issue 50 million yuan in treasury bills in 20 days, but it completed 2/5 of the plan in the first 6 days. Based on this calculation, how many days in advance can the task be completed?
Originally planned to complete 2/5: 20*2/5=8 days
Now to complete 2/5: 8-6=2 days
It now takes: 2÷2/5=5 days to complete the task
The task can be completed in advance: 20-5=15 days
23) A and B are 465 kilometers apart. A car drives from point A to point B. After driving for a period at a speed of 60 kilometers per hour, it accelerates at 15 kilometers per hour. It takes 7 hours to reach point B. How many hours did you drive at 60 kilometers per hour?
Solution: Suppose the vehicle travels at a speed of 60 kilometers per hour for x hours.
60x+(615)(7-x)=465
60x+525-75x=465
525-15x=465
15x=60
x=4
Answer: Driving at a speed of 60 kilometers per hour for 4 hours
24) There are chickens in the cage If there are several rabbits, there will be a maximum of 100 feet. If the chickens are replaced by rabbits, and the rabbits are replaced by chickens, there will be a maximum of 92 feet. How many rabbits and chickens were originally in the cage?
Solution: The rabbits are replaced by chickens, each one loses 2 legs.
(100-92)/2=4,
There are 4 rabbits.
(100-4*4)/2=42
Answer: There are 4 rabbits and 42 chickens.
25) Spiders have 8 legs, and dragonflies have 6 legs and 2 pairs of wings. Cicada has 6 legs and 1 pair of wings. There are currently 18 of these three types of bugs, with 118 legs and 20 pairs of wings. How many of each type of bug are there?
Solution: Suppose there are 18 spiders, y dragonflies, and z cicadas.
There are 18 three kinds of bugs, get:
x+y+z=18... type a
There are 118 legs, get :
8x+6y+6z=118...Form b
With 20 pairs of wings, we get:
2y+z=20...Form c< /p>
Suppose b formula - 6*a formula, we get:
8x+6y+6z-6(x+y+z)=118-6*18
2x=10
x=5
There are 5 spiders,
There are 18-5=13 dragonflies and cicadas.
Change z into (13-y).
Substituting into equation c, we get:
2y+13-y=20
y=7
There are 7 dragonflies.
There are 18-5-7=6 cicadas.
Answer: There are 5 spiders, 7 dragonflies, and 6 cicadas
26) In the activity of learning from Lei Feng, the students did 240 good deeds. Each of the college students did 240 good deeds. They did 8 good deeds, and each of the younger students did 3 good deeds. On average, they each did 6 good deeds.
How many primary school students participated in this activity?
Explanation: The students *** did 240 good deeds, and each of them did 6 good deeds on average.
This means that there are *** 240/6=40 of them
Suppose there are x number of college students and (40-x) number of elementary school students.
8x+3(40-x)=240
8x+120-3x=240
5x+120=240
5x=120
x=24
40-x=16
Answer: There are 24 senior students and 16 junior students.
27) 42 students in a class participated in tree planting. Boys planted an average of 3 trees each, and girls planted an average of 2 trees. It is known that boys planted 56 more trees than girls. How many boys and girls each planted? ?
Solution: Let there be x number of boys and (42-x) number of girls.
3x-2(42-x)=56
3x+2x-84=56
5x=140
x= 28
42-x=14
Answer: 28 boys and 14 girls
28) The salesperson gave a 5-yuan RMB note and a 5-yuan RMB note. The renminbi worth 1 yuan was exchanged for 28 renminbi with a face value of 1 yuan and 1 jiao. How many pieces of each type of renminbi were exchanged?
Solution: Suppose there are x pieces of 1 yuan and (28-x) pieces of 1 dime
x+0.1(28-x)=5.5
0.9x=2.7
x=3
28-x=25
Answer: There are 3 cards for one dollar and 25 cards for one dime.
29) There are 50 pieces of RMB of one yuan, two yuan and five yuan. The total face value is 116 yuan. It is known that there are 2 more yuan of one yuan than two yuan. What are the three denominations of RMB? How many?
Solution: Suppose there are x pieces of 1 yuan, (x-2) pieces of 2 yuan, and (52-2x) of 5 yuan
x+2(x-2) +5(52-2x)=116
x+2x-4+260-10x=116
7x=140
x=20
x-2=18
52-2x=12
Answer: There are 20 cards for 1 yuan, 18 cards for 2 yuan, and 12 cards for 5 yuan.
30) There are 400 movie tickets of 3 yuan, 5 yuan and 7 yuan, each with a value of 1920 yuan. Among them, the number of 7 yuan and 5 yuan tickets is equal, and the three prices of movie tickets are different. How many?
Solution: Let there be x pieces of 7 yuan and 5 yuan each, and (400-2x) pieces of 3 yuan
7x+5x+3(400-2x)=1920
p>
12x+1200-6x=1920
6x=720
x=120
400-2x=160
Answer: There are 160 cards worth 3 yuan, 120 cards worth 7 yuan and 5 yuan each.
31) Use large and small cars to transport goods. Each large car holds 18 boxes and each small car holds 12 boxes. Now there are 18 trucks worth 3024 yuan. If each box is cheaper 2 Yuan, then the value of this batch of goods is 2520 Yuan. Question: How many large and small cars are there?
Solution: Total number of goods: (3024-2520)÷2=252 (boxes)
There are x large cars and (18-x) small cars
18x+12(18-x)=252
18x+216-12x=252
6x=36
x=6
18-x=12
Answer: There are 6 large cars and 12 small cars.
32) A truck can transport ore 20 times a day on sunny days and 12 times a day on rainy days. It has been transported 112 times a day, with an average of 14 times a day. During these days, there are How many days will it rain?
Solution: Number of days = 112÷14=8 days
Suppose x day is a rainy day
20(8-x)+12x=112
160-20x+12x=112
8x=48
x=6
Answer: There are 6 rainy days.
33) A batch of watermelons was shipped and planned to be sold in two categories, large ones at 0.4 yuan per kilogram and small ones at 0.3 yuan per kilogram. The maximum value of this batch of watermelons sold in this way is 290 yuan. If every kilogram The price of watermelons has been reduced by 0.05 yuan. This batch of watermelons can only be sold for 250 yuan. Question: How many kilograms of large watermelons are there?
Solution: Number of watermelons: (290-250) ÷ 0.05 = 800 kilograms
Suppose there are large watermelons x kilograms
0.4x+0.3(800-x )=290
0.4x+240-0.3x=290
0.1x=50
x=500
Answer: Yes Large watermelon 500kg.
34) In a darts throwing competition between A and B, each hit is worth 10 points, and each miss is deducted 6 points. They each throw 10 times, and finally get 152 points, of which A He scored 16 points more than B. Ask: How many times did each of them score?
Solution: A’s score: (152+16)÷2=84 points
B: 152-84=68 points
Suppose A hits x times< /p>
10x-6(10-x)=84
10x-66x=84
16x=144
x=9
Suppose B wins y times
10y-6(10-y)=68
16y=128
y=8 < /p>
Answer: A scored 9 times and B scored 8 times.
35) There were 20 questions in a certain mathematics competition. Each correct answer was worth 5 points. Not only was there no score for a wrong question, but 2 points were deducted. Xiao Ming won this competition. 86 points. Question: How many questions did he answer correctly?
Solution: Suppose he answers x questions correctly
5x-2(20-x)=86
5x-42x=86
7x=126
x=18
Answer: He answered 18 questions correctly.
36 The three households in Building 1 deposited a one-time deposit of 2,700 yuan. The Li family deposited 250 yuan less than the Wang family, and the Wang family deposited 80 yuan more than the Zhang family. How much did each of the three households save?
Solution: Suppose the Wang family has a deposit of x yuan, the Li family has a deposit of x-250, and the Zhang family has a deposit of x-80 yuan.
x+(x-250)+(x-80)=2700
3x-330=2700
3x=270330
< p>3x=3030x=1010
x-250=760
x-80=930
Answer: The Wang family has The deposit is 1,010 yuan, the Li family has a deposit of 760 yuan, and the Zhang family has a deposit of 930 yuan.
37 A cage can accommodate 18 rabbits of the same size and 9 chickens of the same size, or 14 rabbits of the same size and 15 chickens of the same size. If it is specially used as a rabbit cage , how many rabbits can it accommodate at most?
Solution: Let the size of the cage be m, one rabbit occupies space x, and one chicken occupies space y.
m=18x+9y< /p>
m=14x+15y
Obtain: 18x+9y=14x+15y
4x=6y
2x=3y
p>y=2/3x
So: m=18x+9*2/3x
m=18x+6x
m=24x
Answer: It can accommodate up to 24 rabbits.
38 A, B, and C. A’s age is 2 times older than B’s age and 3 years older. B’s age is 2 years younger than C’s age. The sum of the ages of the three is 109 years. Each of the three is 109 years old. How old are you?
Solution: Let B’s age be x, A’s age be 2x+3, and C’s age be (x+2)/2.
x+2x+ 3+(x+2)/2=109
3x+1/2x+4=109
7/2x=105
7x=210< /p>
x=30
2x+3=63
(x+2)/2=16
Answer: A is 63 years old. B is 30 years old and C is 16 years old.
The 1st, 23rd and 3rd Young Pioneers Squadron *** eliminated 200 rodents. The 2nd Squadron eliminated 5 rodents, twice twice as many as the 1st Squadron. The 3rd Squadron set up the 1st Squadron to eliminate X rodents, and the 2nd Squadron eliminated X rodents. The rats were exterminated 2x+5, and the third squadron exterminated 3x+9 rats.
Note: x+2x+5+4=3x+9!
x+2x+5+3x+9=200
6x+14= 200
6x=186
x=31
2x+5=67
3x+9=102
< p>Answer: The first squadron exterminated 31 rats, the second squadron exterminated 67 rats, and the third squadron exterminated 102 rats. The number of rats killed is 4 more than that of the first and second squadrons combined. How many rats were killed by each of the three squadrons?39 A travels 12 kilometers per hour, and B travels 8 kilometers per hour. On a certain day A goes from East Village to West Village, and B goes from West Village to East Village at the same time. It is known that when B arrives in East Village, A has already arrived in West Village for 5 hours. Find the distance between the east and west villages...
Suppose A walked The time is X, then
12 * /p>
40 A ship travels 75 kilometers per hour from point A to point B and 50 kilometers per hour when returning. Find the average round-trip speed of the ship.
Suppose it took X hours to go
Average speed = total length/total time Then: the total length is 75 * X * 2 = 150 + 75X / 50 = 2.5 X
So the average speed is 150 Zhou Yan has 13 stickers, and after Liu Min gives Zhang Xin 15 stickers, the three people have the same number of stickers. How many more stickers does Liu Min have than Zhang Xin?
Suppose Zhou Yan has X stickers, then Liu Min has X - 13 + 15 = X + 2 pictures, then Zhang Xin has X - 13 - 15 = X - 28 pictures
Then the difference between the two people is X - X + 28 = 28
42 A has a deposit of 520 yuan, and B has a deposit of 240 yuan. After they withdraw the same money, A's remaining money is 5 times that of B's ??remaining money. How much money do they withdraw at one time?
Suppose X yuan is withdrawn
520 - X = (240 - X) * 5 The result is Car A travels in the same direction. Car A travels 6 kilometers per hour faster than car B. Car A arrives at place B 45 minutes earlier than car B. When car B arrives at place B, car A travels 36 kilometers away from place B. From point C, it is ( ) kilometers from point A to point C.
Solution: It can be seen from the meaning of the question: A takes 36÷6=6 hours from A-C, and the speed is 36÷3/. 4=48km/h
So the formula: 48×6=288 (km)
44 Yang Ping walks to school from home on time every day, and Uncle Li also goes out for a walk on time every morning. , the two walked toward each other. Yang Ping walked 80 meters every minute, and Uncle Li walked 70 meters every minute. They met on the way every day. One day, Yang Ping went out early, so he met Uncle Li 8 minutes earlier than usual. Yang Ping left the house ( ) earlier than usual.
Solution: It can be seen from the meaning of the question: Yang Ping alone has to walk out of the 8-minute distance for two people in advance, so the formula is: (870)×8÷80=15 (minutes )
45 Two cars A and B leave from stations A and B respectively along the highway and go towards each other. It is known that the speed of car A is 1.5 times that of car B. When two cars A and B arrive, The times at station C on the way are 5:00 and 16:00 respectively. The time when the two cars meet is ( ).
Solution: (Picture omitted) From the meaning of the question, we can know: when A reaches point c, B reaches point d, they meet at point e. It takes B 11 hours to go from
d to c, and the distance ratio of ce:ed is: 3:2, so the formula is:
5+11×2/5=9 Point 24
46 A walks from point A to point B, and person B rides a bicycle from point B to point A. An hour later, the two meet on the way. After B arrives at point A, he immediately returns to point B. Catch up with A 40 minutes after the first encounter. B goes to B and then turns back to A. Then B will meet A again in ( ) minutes after catching up with A.
Solution: It can be seen from the meaning of the question: A and B can walk the entire distance from A to B in 1 hour. Then when they met for the third time, *** walked 3 full distances, so 60×3-60-40=80 (minutes)
[Replace the division sign with # and the multiplication sign with X
47 There are 90 table tennis balls in the sports supplies. If two are put in a box, can they be filled exactly? If five are put in a box, can they be filled exactly? Why?
90 ÷ 2=45 boxes 90÷ 5=18 boxes
Answer: If you put one box every two, it can be completely filled. If you put one box every five, it can be completely filled. Because 90 is divisible by five.
48 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 fully loaded.
49 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.
50 fifth-grade students planted trees, and groups of 13 or 14 people were divided into groups. How many fifth-grade students participated in tree planting?
13×14=192 people
13×14=192 people
p>
Answer: There are at least 192 people in fifth grade participating in tree planting.
51 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: After 240 minutes, the two cars will be 300 kilometers apart.
p>52 Two engineering teams are required to excavate a 119-meter-long tunnel together. The two teams are constructing from both ends. Team A digs 4 meters per day and Team B digs 3 meters per day. How many days will it take to complete the tunnel? The tunnel is dug?
Solution: Suppose the tunnel is dug in X days
3X+4X=119
7X=119
X= 17
Answer: It took 17 days to dig the tunnel.
53 There are 140 people in the school chorus and dance team. The number of the chorus team is 6 times that of the dance team. The dance team How many people are there in the team?
Explanation: Suppose there are X people in the dance team
6X+X=140
7X=140
X =20 people
Answer: There are 20 people in the dance team.
From here on it is not an equation problem.
54 Two brothers went from home to the gymnasium at the same time. The road is 1300 meters long. The elder brother walks 80 meters per minute. The younger brother rides a bicycle at a speed of 180 meters per minute to the gymnasium and returns immediately. He meets his elder brother on the way. How long did the elder brother walk?
1300× 2=2600 meters 2600÷ (1880)
=2600÷ 260
=10 minutes
Answer: My brother walked for 10 minutes at this time. < /p>
55 On Children’s Day, Teacher Wang bought 360 biscuits, 480 candies, and 400 fruits, and made exquisite small gift bags to give to children as gifts. How many small gift bags can be made at most?
3648400=1240 pieces
Answer: You can make up to 1240 small gift bags.
56 Naughty bought 40 balloons and invited classmates to come home to compete. Balloons. In order to divide the balloons equally, Naughty should invite several classmates 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.
57 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 field How many corn plants can be planted on one piece of land?
(15+24)× 18÷ 2=351 square meters
351× 9=3195 plants
Answer: This land can grow 3159 corn plants.
58 The number of students in a certain class is less than 100. When lining up, there are exactly one more students in each row of 5, 4 and 3. This class has How many people?
5× 4× 3=60 people 61=61 people
Answer: There are 61 people in this class.
59 Wang Yue has one A box of chocolate candies, 7 pieces each time, 5 pieces, 3 pieces each have 1 piece left. How many chocolate candies are there in this box?
7× 5× 3=105 pieces 105+1=106
Answer: There are at least 106 pieces in this box of chocolate candies.
60 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 A square brick with a side length of 30 cm, please do the math: How many such square bricks 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
150× 12=1800 square decimeters 3× 3=9 square decimeters
1800÷ 9=200 200 × 3 = 600 yuan
Answer: 200 such square bricks are needed, which cost 600 yuan.
61 There are two parallelogram experimental fields with equal areas, one with a base The length is 70 meters and the height is 45 meters. The bottom side of the other piece is 90 meters long. How many meters is the height?
70 × 45=3150 square meters 3150#90=35 meters
Answer: The height is 35 meters.
62 A batch of steel pipes are stacked in a pile. There are 10 steel pipes on the bottom layer. One less pipe is placed on each upper layer, and 5 steel pipes are placed on the top layer. How many steel pipes are there in this batch?
10-5+1=6 layers (15)× 6÷ 2
=15× 6÷ 2
=90÷ 2
p>
=45 pieces
Answer: There are 45 steel pipes in this batch.
63 pieces have a length, width and height of 90 cm, 30 cm and 15 cm respectively. If a rectangular piece of wood is sawn into cubes of the same size without any leftovers, what is the longest edge length of the sawn cube in centimeters? How many cubes like this can be sawn into?
If a rectangular piece of wood with a length, width, and height of 90 cm, 30 cm, and 15 cm is sawed into cubes of the same size without any leftovers, what is the longest edge length of the cube? centimeter? How many cubes like this can be sawn into?
/p>
The number of cubes that can be sawn into is: (90/15) × (30/15) × (15/15) = 6*2*1 = 12 (blocks)
64 A pool has an inlet pipe and an outlet pipe. Opening both pipes together can fill the empty pool in 8 minutes. Opening the outlet pipe alone can drain the full pool in 24 minutes. Opening the water inlet pipe alone can fill the empty pool in ( ) minutes.
Solution: Assume that the empty pool can be filled with a single water inlet pipe for X minutes. According to the question: 1/X-1/24=1/8
Solution: X=6
That is, the empty pool can be filled up by just opening the water pipe for 6 minutes.
The sixth grade class of 65 Hongwei Brigade donated 378 yuan to the "Hope Project", accounting for 378 yuan of the total donations in the school. 21%, how much does the whole school donate?
Answer: The amount of donations from the whole school: 378/21%=1800 yuan.
66 There are two barrels of oil, A and B. If barrel A pours 5 kilograms into barrel B, then barrel B is 10 kilograms more than barrel A. At this time, barrel A's oil accounts for 80% of barrel B's oil. Originally, A's How many kilograms of oil is in the barrel?
Solution: The original number of kilograms of oil in barrel A:
5*2/(1-80%)-5=45 kg.
67 Top 5 The average daily mileage is 0.25KM, and the final 8 days are 2.65KM. How many kilometers do you cover on average every day?
An average of 0.25KM was repaired every day in the first 5 days, and 2.65KM was repaired in the next 8 days. How many kilometers do you cover on average every day?
（5*0.25+2.65）/(5+8）
=（1.25+2.65）/13
=3.9/13
=0.3
An average of 0.3KM is repaired every day.
68 Xiao Ming and his father went to the park to play. When buying the ticket, his father paid 20 yuan and got 3.5 yuan back. If the student ticket price in the park is half of the adult ticket price, then the student ticket and the adult ticket are each How much is it?
One *** costs 20-3.5=16.5 yuan
Because the student ticket is half of the adult ticket
So an adult ticket You can buy two student tickets
So you can buy three student tickets for 16.5 yuan
So one student ticket costs 5.5 yuan
So one The price of an adult ticket is 11 yuan
69 There is a vegetable field and a wheat field. Adding half of the vegetable field and 1/3 of the wheat field together is 13 hectares. Add 1/3 of the vegetable field and 1/3 of the wheat field. Half of the wheat field adds up to 12 hectares. How many hectares are there in the vegetable field?
Suppose the vegetable field is /(1/3), that is, 39-(3/2)*X, and based on "1/3 of the vegetable field and half of the wheat field add up to 12 hectares", the equation is: (1/3 )*X+(1/2)*(39-(3/2)*X)=12, find X=18.
70 It is known that basketball, football, and volleyball average 36 yuan each, Basketball is 10 yuan more than volleyball. Football is 8 yuan more than volleyball. How much is each football?
Basketball, football, and volleyball cost an average of 36 yuan each. Basketball costs 10 yuan more than volleyball. Football costs 8 yuan more than volleyball. How much does each football cost?
Solution: Let each football cost X yuan
(X-8)+(X-8+10)+X=36*3
3X- 6=108
3X=114
X=38
Answer: Each football is 38 yuan.