8 divided by 4/5= 10 (km/)
4/5 divided by 8=0. 1 (kg)
3. A motorcycle 1/2 hours for 30 kilometers. How many kilometers does it travel per hour? How many hours does it take him to drive 1 km?
30 ÷1/2 = 60km1÷ 60 =1/60h.
7. When water turns into ice, its volume is110, 2. 16 cubic meters of ice melts into water, what is its volume?
2.16/(1+11) =1.98 (m3)
9. The price reduction of TV sets in 200 yuan is 2/ 1 1. What's the price of this TV set now?
The original price is
200 ÷ 2/ 1 1 = 2200 yuan
The current price is
2200-200 = 2000 yuan
10。 Car A has traveled more than 2/5 kilometers from A to B.. At this time, there are still 70 kilometers from B. How many kilometers are there between A and B?
Full time
1-2/5=3/5
be
20+70 = 90km
Distance between Party A and Party B
90 ÷ 3/5 =150km
1 1. Xiaoming reads books. On the first day, he read 28 pages. The next day, he read the whole book 1/5 (1). Last two days, * * * read 3/8 (8/3) of the whole book. How many pages does this book have?
What I read on the first day accounted for the whole book.
3/8- 1/5=7/40
This book * * * has
28/7/40 = 160 page
13. A barrel of oil, after eating 7/ 10, added 15 kg. At this time, the oil in the barrel is exactly half of that in a barrel. How much does this barrel of oil weigh?
15 ÷ (7/10-1/2) = 75 (kg)
18. A motorcycle travels 64 kilometers per hour. It takes 3/4 hours to find this speed from a to b. What is the distance between a and b?
64× 3/4 = 48km
19. The fruit shop sold a batch of fruits in two days. On the first day, 3/5 of the total fruit weight was sold, 30 kilograms more than the next day. How many kilograms are there in this batch of fruit?
If you sell 3/5 of the total weight of fruit on the first day, you will sell 2/5 the next day.
3/5-2/5= 1/5, the first day is more than the second day,
30 ÷ 1/5 = 150kg，
The formula is,
1-3/5=2/5
3/5-2/5= 1/5
30/1/5 =150kg
20. Jessie Primary School has 9 10 students, seven quarters of whom are girls. How many are girls? How many boys are there?
9 10 * 4/7 = (9 10 * 4)/7 = 520 ...
9 10-520=390 ... boys
2 1. A rectangular piece of land is 60 meters long and 2/5 wide. What is the area of this land?
4/5*5/8=(4*5)/(5*8)= 1/2 (m)
4/5- 1/2 = 8/ 10-5/ 10 = 3/ 10(m)
22. The ratio of red goldfish to black goldfish in the goldfish pond is 7:3. There are 9 black goldfish. How many red goldfish are there?
9 ÷ 3× 7 = 2 1
Grade 23.6 students 132, in which the ratio of male to female students is 6: 5. How many boys and girls are there in the sixth grade?
132 ÷ (6+5) = 12 people
Male students have
12× 6 = 72 people
Female students have
12× 5 = 60 people
24. The ratio of A to B is 2:3, and the ratio of B to C is 4:5. Find the ratio of a to C.
A: B = 2: 3 = 8: 12。
B: C = 4: 5 = 12: 15。
A: B: C = 8: 12: 15.
A: C = 8: 15
25. The number of trees planted in Jiefang Road Primary School this year is 65438+ 0.2 times that of last year. Write down the ratio between the number of trees planted in this primary school this year and the number of trees planted last year.
1.2: 1=6:5
The number of students in a class is between 40 and 50, and the ratio of male to female is 5:6. How many boys and girls are there in this class? ..
Because the number of people is an integer,
So the class size can be divisible by 5+6 = 1 1.
So the class size is 44.
Boys have
44 ÷ (5+6) × 5 = 20 people
Girls have
44-20 = 24 people
32. There are 465 students in a school, of whom 2/3 are girls and 20 are less than 4/5 boys. How much is the male and female?
Two thirds of the girls are 20 less than four fifths of the boys.
Girls are less than boys by 20/(2/3)= 30(4/5)/(2/3)= 6/5.
Boys have
(465+30)/( 1+6/5)=225 (person)
Girls have
465-225=240 (person)
33. For a manuscript, 1 7 was typed on the first day, and 2/5 was typed on the second day. The next day was nine pages more than the first day. How many pages are there in this manuscript?
9 divided by (2/5-65438/7+0)
=9 divided by 9 of 35.
=35 pages
This manuscript has 35 pages.
34. On a piece of land, the aspect ratio is 8: 5, and the length is 24 meters more than the width. How many square meters is this land?
If the length is 8 and the width is 5, it is more than 3, which is 24 meters.
Then one is: 24/3=8 meters.
That is, the length is 8 * 8 = 64m and the width is 8 * 5 = 40m.
Area: 64 * 40 = 2560m2.
35. If there are 25% more boys than girls, how many girls are less than boys?
Female students 1.
For boys, 1+25% = 125%.
The number of girls is less than that of boys (125%-1) ÷125% = 20%.
36. This breeding factory has raised 65,438+0,987 pigs this year, which is three times less than that of last year, that is, 245 pigs. How many more pigs have been raised this year than last year?
Raising pigs last year: (1987+245)/3=744.
Raise more pigs this year than last year: 1987-744= 1243.
37. The ratio of Xiao Wei and Xiaoying's donation to Project Hope is 2:5. Xiaoying donated 35 yuan. How much did Xiao Wei donate?
Let Xiao Wei donate X yuan.
So 2:5=X:35: X= 14 yuan Xiaowei donated 14 yuan.
38. All three averages are 8.4, of which the first number is 9.2, and the second number is 0.8 less than the third number. What is the third number?
The third number is 8.4.
Solution: Let the third number be x and the column equation be:
3*[9.2+(x-0.8)+x]=8.4
The solution is x=8.4.
39. There are two ropes. The length of the first rope is 1.5 times that of the second rope, and the second rope is 3 meters shorter than the first rope. How long are these two ropes?
If the length of the second root is x meters, the length of the second root is 1.5x meters.
1.5x-x=3
0.5x=3
x=6
6× 1.5 = 9 (m)
The first one is 6 meters long.
The second one is 9 meters long.
40. The construction team built a road, and the repaired length and the remaining ratio were 4: 5. If you build another 25 meters, it will just reach the midpoint of this road. What is the total length of this road?
4+5=9
Solution: Let this road be x meters long:
(5/9-4/9)x=25
1/9x=25
x=225
This road is 225 meters long.
1. To make a cylindrical iron drum without a cover, the bottom diameter is 4 decimeters and the height is 5 decimeters. What is the minimum area required for tin?
3. 14 ×(4÷ 2)×(4÷ 2)+3. 14× 4× 5 =75.36
2. A cylindrical pool, the wall and bottom of the pool should be inlaid with tiles. The diameter of the bottom is 6m, and the depth of the pool is1.2m.. What is the maximum area of tiles?
3. 14× (6÷ 2)× (6÷ 2)+3. 14× 6 × 1.2=50.838
3. How many square centimeters of iron sheet should be used to make a cylindrical ventilation pipe with a bottom diameter of 20 cm and a length of 50 cm?
3. 14× 20× 50=3 140
It is known that it takes five hours for a boat to sail 60 kilometers downstream and nine hours to sail 72 kilometers upstream. Now the ship is from the upstream city A to the downstream city B. It is known that the waterway distance between the two cities is 96 kilometers. When sailing, the boatman threw a board into the water. How far is the plank from B city when the ship arrives?
It takes five hours to sail 60 kilometers along the river.
Downstream speed: 60÷5= 12
It takes nine hours to sail 72 kilometers against the current.
Upstream speed: 72 ÷9=8
Water velocity: (12-8)÷2=2.
Now the ship is from the upstream city A to the downstream city B. It is known that the waterway distance between the two cities is 96 kilometers. When sailing, the boatman threw a board into the water. How far is the plank from B city when the ship arrives?
96-2×(96÷ 12)=80
Ships from upstream city A to downstream city B: (96÷ 12)
The distance between each row of boards is 2×(96÷ 12).
5. A ship sails back and forth between A and B, with a downstream speed of 30 kilometers per hour and a countercurrent speed of 10 kilometers per hour. What is the average speed of this ship between A and B?
Suppose the distance is 30 kilometers (other numbers are ok).
Round trip distance ÷ round trip time = round trip speed
(30+30) ÷(30 ÷30 +30 ÷ 10)= 15
Be careful not to take the sum of speeds as distance, and assume a number without distance.
6. A batch of apples sold a third on the first day and a quarter the next day. I bought 24 kilograms more on the first day than on the second. How many kilograms are these apples?
24 ÷( 1/3- 1/4)=288
7. A batch of bananas is sold for a third on the first day and a quarter on the second day. The second day was less than the first day 18kg. How many kilograms are these bananas?
18 ÷( 1/3- 1/4)=2 16
8. One third of a batch of fruit was sold on the first day, and 72kg was sold on the second day, leaving 120kg. How many kilograms are there in this batch of fruit?
(72+ 120)÷( 1- 1/3)=288
9. On the first day, I sold one third of a batch of fruits, leaving 192kg. How many kilograms did you sell on the first day?
192÷( 1- 1/3)× 1/3=96
10. On Sunday, Xiaoming bought some apples to entertain his classmates and ate 5/9 of them. Then his mother came home and brought back 3 1. As a result, the number of apples is now 20% more than before. How many apples did Xiaoming buy?
Suppose Xiaoming bought x apples.
I ate it and brought back 3 1 apple (current number of apples)-previous number = 20% of previous number.
( 1-5/9)×X+3+3 1-X = 20% X
X=45
1 1. If Party A and Party B work together, a project can be completed within 3 days; if Party C works alone, it will take 12 days. How many days will it take for Party A, Party B and Party C to complete all the projects?
Both parties can complete the project of 1 within 3 days.
The working efficiency of A and B is 1/2÷3= 1/6.
If C works alone, the project can be completed in 12 days.
The efficiency of C is1÷12 =112.
Ergonomics of a, b, c and1/6+/12 =1/4.
How many days will it take for Party A, Party B and Party C to complete all the projects?
1÷ 1/4=4
12. Build a flower bed with an outer diameter of 2.2m, an inner diameter of 2m and a depth of 0.5m.. What is the floor area of this flower bed? How many cubic meters of land does it take to fill the flower bed?
The floor area of the flower bed is also the area of the ring.
3. 14×(2.2÷2)×(2.2÷2)-3. 14×(2÷2)×(2÷2)= 0.6594 m2。
Volume large circle volume-small circle volume
3.14× (2.2 ÷ 2 )× (2.2 ÷ 2 )× 0.5-3.14× (2 ÷ 2 )× (2 ÷ 2 )× 0.5 = 0.3297 cubic meter
13. The bottom circumference of cylindrical wood is 12.56 decimeter. The height is 4 meters.
1. What is the surface area?
Radius: 12.56 ÷3. 14÷2=2 decimeters.
2 decimeter =0.2 meter 12.56 decimeter = 1.256 meter
3.14× 0.2× 0.2+1.256× 4 = 5.2752 m2.
2. What's the volume?
4 meters =40 decimeters
3. 14 ×2 ×2×40=502.4 cubic decimeter
3. If it is cut into three small cylinders, how many square decimeters will the surface area increase? .
Four bottom areas are added.
Radius: 12.56 ÷3. 14÷2=2 decimeters.
3. 14 ×2 ×2×4=50.24 square decimeter
14. There are two bags of noodles. The weight of the second bag is 6/7 of that of the first bag. If you take 7 kilograms from the first bag and put it in the second bag, the weight of the two bags will be equal. How much do these two bags of noodles weigh?
The weight of the second generation is 6/7 of that of the first generation bag.
Imagine the first bag as a unit of 1 and divide it into 7 parts on average. The second bag is 6 servings.
Together, 7+6= 13 copies.
Change the number of copies from 13 to 26 or any other even number.
Two bags of noodles ***26, the first bag 7 ×2= 14 and the second bag 6×2= 12.
Take 7 kg from the first bag and put it in the second bag, and the weight of the two bags will be equal.
14 - 1 = 12 + 1.
1 is 7 kg.
The first bag 14 volume 7× 14=98.
The second bag 12 volume 7× 12=84.
15. On the map with the scale of 1: 600000, the distance between A and B is 9 cm, and two trains start from A and B relatively at the same time, with a speed of 57 kilometers per hour and a speed of 43 kilometers per hour. In a few hours, the distance between the two cars will be 40 kilometers.
1: 6000000 = distance on the map: actual distance.
1: 6000000 = 9: Actual distance
Actual distance: 9× 6 million = 54 million cm = 540 km.
(540-40)÷(57+43)=5
16. A monkey is eating peaches in a basket. The first monkey takes out half sum 1, the second monkey eats the remaining half sum 1, and the third monkey eats the last half sum and 3. At this time, the peaches in the basket have just finished eating. How many peaches are there in the basket?
The third monkey ate the last half and three, when the peaches in the basket had just finished eating.
3+3=6
The second monkey ate the remaining half. 1.
(6+ 1)×2= 1 14
The first monkey takes out half, 1.
( 14+ 1)×2=30
Draw a line segment from back to front.
17. Dad runs 200 meters more than Zhang Jun and less than Mom 100 meters. Who runs more, Zhang Jun or his mother?
Dad = twice as much as Zhang Jun +200m.
Twice that of Zhang Jun = Dad -200m.
Zhang Jun = (Dad-200m) ÷2
Zhang Jun = Dad ÷2-200÷2
Zhang Jun = Dad ÷2- 100
Dad = 30 times that of mom-100m
30 times that of mom = dad+100m.
Mom = (Dad+100 m) ÷30
Mom = Dad ÷30+ 100 meter ÷30
Mom = Dad ÷30+ 10/3
18. After 70% of the water in a bucket is used up, pour 10 kg of water into the bucket, which is exactly half of the original whole bucket. How many kilograms was there in that bucket of water?
Suppose a bucket of water has x kilograms.
( 1-70%)X+ 10 = 1/2X
X =50
19. Party A and Party B * * * have several stamps, and the number of stamps known by Party A accounts for 3/7 of the total. If Party B gives the stamps of 10 to Party A, the number of stamps of both people is equal. How many stamps are there in A and B?
The number of stamps in A accounts for 3/7 of the total.
The total is 7.
A: 3 copies.
B: Four copies.
Suppose a is 3X and b is 4X.
4X- 10=3X+ 10
X =20
A is 3x...60.
B is 4x...80.
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These are always enough ~
It seems that everyone has an answer and a process ~
I hope it helps you.
thank you