A pedestrian who walks 1 meter per second and a cyclist who walks 3 meters per second go south together. Then a train came, passing pedestrians in 22 seconds and cyclists in 26 seconds. Find the length of the train body.

Let the speed of the train be x m/s,

Trains, pedestrians and cyclists are all heading south. The length of the train is the distance between pedestrians and cyclists, that is, the meeting of the front and the separation of the rear.

It took 22 seconds for the train to overtake pedestrians. During these 22 seconds, the train ran 22X meters, and pedestrians also walked in the same direction 1 * 22 = 22m, so if pedestrians were stationary, the train ran (22X-22) meters.

It took the train 26 seconds to overtake the cyclist. In these 26 seconds, the train ran 26X meters, and the cyclist also walked in the same direction by 3 * 26 = 78m, so if the cyclist was stationary, the train ran away (26X-78).

So 22X-22 = 26X-78.

The solution is X= 14.

That is, the train speed is14m/s.

When the train passes pedestrians, the train travels south at the speed of 14m/s, and pedestrians also travel south at the speed of 1m/s, so the speed of the train relative to pedestrians should be14-1=13m/s. As mentioned earlier, the train passes pedestrians. Therefore, the length is 13m/s * 22s = 286m.

The examination paper of cylinder and cone exercises in the next semester of grade six

Cylinders and cones (1)

1, expand the side of the cylinder to get a (). The length of a rectangle is equal to () of a cylinder, and the width of a rectangle is equal to () of a cylinder. The side area of a cylinder is equal to () times ().

2, a cylinder is divided into several equal parts, can be spelled into an approximate (), cuboid () is equal to the cylinder (), cuboid (

) is equal to () of cylinder, and () of cuboid is equal to () of cylinder. Because the volume of a cuboid = () ×), the volume of a cylinder = ()×).

3. The diameter of the bottom surface of the cylinder is 5cm and the height is 8cm. The bottom area of this cylinder is (), and the perimeter of the bottom surface is ().

The height of the cone is 6 decimeters, and the radius of the bottom is 4 decimeters. The circumference of the bottom of this cone is () and the bottom area is ().

5. Use a rectangular piece of paper with a length of 15cm and a width of 12cm to form a cylinder. The circumference of the cylinder bottom is (), the height is (), and the side area is ().

6. When the diameter of the bottom surface of the cylinder is enlarged by 4 times, its side area is enlarged by () times and its volume is enlarged by () times.

7. The cylinder is a square with a length of 9.42 decimeters after being unfolded. The diameter of the bottom of this cylinder is (), and the area of the bottom is ().

8. The radius of the bottom surface of the cylinder is 1 decimeter and the height is 2.5 cm. Its side area is () and its volume is ().

9. The circumference of the bottom of the cylinder is 94.2 cm and the height is 25 cm. Its side area is (), its surface area is () and its volume is ().

10, a cylinder with a base diameter of 5cm, a height of 12cm, a base perimeter of (), a lateral area of (), a base area of () and a volume of ().

1 1, a cylinder with a bottom radius of 5cm, a height of 12cm, a bottom perimeter of (), a lateral area of (), a bottom area of () and a volume of ().

12, the height of a cylinder is 18 cm, the radius of its bottom surface is high, and its side area is ().

13, a section of cylindrical wood, the bottom area is 78.5 square decimeters, the height is 20 cm, and its volume is ().

14, a cylinder, with a rope around its bottom circumference 3. 14 meters, 4 meters high, the volume of this cylinder is ().

15, the bottom area of a cylinder is 28.26 square meters, the height is (), and the volume is 84.78 cubic meters.

16, cylindrical teacup without cover, bottom diameter 8 cm, height 10 cm. Its volume is ().

17. The radius of the bottom of the cylinder is 2.5 cm and the height is 6 cm. Divide the cylinder into two parts equally along the diameter of the bottom surface of the cylinder. The surface area of two semi-cylinders is increased by (), and the volume of each semi-cylinder is ().

18, a section of cylindrical iron chimney is 1.5m long and 0.2m in diameter. To make 500 such chimneys, at least iron () square meters should be used.

19. There are eight identical cylindrical wooden columns in the hall, each with a height of 5 meters and a bottom circumference of 2.7 meters. If you can draw 4.5 square meters per kilogram of paint, then you need () kilograms to draw these wooden pillars.

20. It takes about () square meters of iron to make a cylindrical iron drum with a height of 6 decimeters and a bottom radius of 1.8 decimeters. (Number reserved 10 square decimeter)

2 1. The height of a style in the square is 3.5 meters, the radius of the bottom is 0.8 meters, and the side and top of the style are covered with plastic flowers. If there are 42 flowers per square meter, there are () flowers in this style.

22. A cylindrical oil drum with a bottom diameter of 0.6m and a height of 65438 0 m.. It takes at least () square meters of iron to make this oil drum. If the weight of gasoline per liter is 0.85 kg, this oil drum can hold () kg of gasoline.

23. The cylindrical lantern has a base diameter of 24 cm and a height of 30 li. Stick colored paper on the bottom and side of the lantern, at least () square centimeters.

Cylinders and cones (2)

24. Cylindrical oil drums, measured from the inside, have a bottom diameter of 40 cm and a height of 50 cm. This oil drum can hold 100 liter of oil. If 1 liter of oil weighs 0.85 kg, this oil drum can hold () kg of oil.

25. Cylindrical pool, measured from the inside, with a bottom diameter of 8m and a depth of 3.5m.. The bottom and periphery of the pool are coated with cement. The pool area is (), and the plastering area is (). This swimming pool can store up to 1 00000 tons of water (1 m3 weight1ton).

26, a cylindrical barrel, 6 cents high. The ring length at the bottom of the barrel is about 15.7 decimeter. It takes at least () square decimeter to make this barrel. This can hold 20 liters of water.

27. The front wheel of the roller is cylindrical, with a wheel width of 1.6m and a diameter of 0.8m When the wheel rolls once, the area of the road is (). If the wheel rolls 20 times per minute, it will advance () meters per minute.

28. Cut a 6-centimeter cube into the largest cylinder. The volume of this cylinder is () and the surface area is ().

29. How many pieces of iron do you need to make the cylindrical object below? (1) Oil drum: the bottom radius is 4 decimeter, the height is 12 decimeter, and the iron sheet area is (). ⑵ Uncovered bucket: the bottom diameter is 40 cm, the height is 50 cm, and the iron sheet area is (). (3) Ventilation duct: the section circumference is 0.628m, the height is 1.2m, and the iron sheet area is ().

There is a cylindrical water storage tank in the school, and its side is surrounded by a square iron sheet with a side length of 6.28 decimeters. This water tank can hold () litres of water at most.

3 1, cylindrical mailbox, measured from the inside, with a bottom diameter of 4 decimeters and a height of 5 decimeters. If each liter of gasoline weighs 0.75 kg, this oil drum can hold () kg of gasoline.

32. Make a cylindrical learning tool with plasticine. The bottom of the cylinder is 4 cm in diameter and 6 cm in height. If you make another rectangular box, so that the plasticine cylinder can just fit in, you need at least () square centimeters of cardboard.

33, a cylindrical cans, bottom diameter 12 cm, 8 cm high, around the sticker, the area of the sticker is ().

34. One side of the cylinder expands into a rectangle. The length of the rectangle is 9.42 cm and the width is 3 cm. The side area of this cylinder is (), the surface area is () and the volume is ().

35. Roll a rectangular paper with a length of 12.56 cm and a width of 9.42 cm into a cylinder with a volume of () or ().

36. Saw a 5-meter-long cylindrical wood into four sections, and the surface area increased by 60 square decimeters. The volume of this wood is ().

37. How much can the roller of the roller turn in one week? The road surface is a cylinder ()

38. The length of a rectangle is 6 cm and the width is 2 cm. The volume obtained by rotating a cylinder on its length is ().

39. The bottom of a cuboid is a square with a side length of 4 decimeters and a height of 8 decimeters. It is completely immersed in a cylindrical container filled with water, and the bottom area of the container is 32 square decimeters. The water level will rise by () cm.

40. Make an uncovered cylindrical barrel with a height of 5% and a bottom circumference of 12.56 decimeter with an iron sheet of at least () square centimeters. This barrel can hold 20 kilograms of water. (The weight of each liter of water is 1 kg)

4 1. Make five chimneys of the same size with iron sheets, each section is decimeter long and the bottom diameter is 1 decimeter. At least iron () is needed.

42, a cylindrical steel, cut 1 m after measuring its cross-sectional diameter is 20 cm, cut volume accounts for 40% of this steel, the original volume of this steel is () cubic decimeter.

43. A cylindrical reservoir with a bottom circumference of 25.12m, a water depth of 2.4m and a water surface of 0.9m. The reservoir holds () tons of water. (1 m3 water weight 1 ton)

44. Uncovered cylindrical iron drum, bottom radius 15cm, height 50cm. To make such a bucket, you need at least one () square centimeter of iron sheet, and this bucket can hold at most () kilograms of water. (weight per liter of water is 1kg) (figures are rounded off)

45. The side area of the cylinder is 188.4 square meters, the radius of the bottom is 2 decimeters, and the height is () decimeters.

46. The plastic shed is covered with plastic film, with a length of 15m and a cross section of a semicircle with a radius of 2m. It takes about () square meters of plastic film to build this greenhouse, and the space of this greenhouse is about ().

Cylinders and cones (3)

47. The bottom area and height of cylinder and cone are equal respectively. The volume of the cone is the volume of the cylinder (), and the volume of the cylinder is the volume of the cone ().

48. The volume of a cylinder is 15 cubic centimeter, and the volume of a cone with the same height as its bottom surface is ().

49, the volume of a cone is 7.2 cubic meters, and the volume of a cylinder with equal bottom and equal height is ().

50. The radius of the cone bottom is 6 cm, the height is 20 cm, and the volume is ().

5 1, the volume of a cone is 24 cubic decimeters, the bottom area is 12 square decimeters, and the height of this cone is ().

52. The diameter of the cone bottom is 8 decimeters, and the height is 15 decimeter. The volume of this cone is (), and the volume of a cylinder with the same height as the bottom is ().

53. The side of the cylinder is a square with a side length of 3. 14 decimeter, the height of the cylinder is (), and the bottom area is ().

54. If the height of a cylinder is shortened by 3cm, the surface area will be reduced by 94.2cm2 and the volume will be reduced ().

55. A cone and a cylinder are equal in height. If the volume of the cylinder is 2.7 cubic meters, then the volume of the cone is (); If the volume of the cone is 2.7 cubic meters, then the volume of the cylinder is ().

56. Fill a conical container 30 cm high with water and pour it into a cylindrical container with the same height as the bottom. The height of water is ().

57. The length of a rectangle is 6 cm and the width is 2 cm. The volume obtained by rotating a cylinder on its length is ().

Casting a cylindrical aluminum block into a cone, its () remains unchanged.

58. Cylinders and cones are equal in height, and their volume is 60 cubic centimeters. Then, the volume of the cylinder is (), and the volume of the cone is ().

59. Saw a 5-meter-long cylindrical wood into four sections, increasing the surface area by 60 square decimeters. The volume of this wood is ().

60. Cone-shaped sand pile with a bottom area of16m2 and a height of 2.4m.. If each cubic meter of sand weighs 1.7 tons, then this pile of sand weighs () tons.

6 1. A cone with a height of 12cm is divided into two parts with the same size and shape along the bottom diameter, and the surface area is increased by 192cm2. The volume of this cone is ().

62. Cylindrical wood with a bottom diameter of 8 cm and a height of 9 cm is cut into the largest cone. The volume of this cone is (), and the volume of the cutting part is ().

63. Cut the cylinder into the largest cone, and its volume is cylindrical () The volume of the cut part is cylindrical () The volume of the cut part is conical ().

64. (1) The volume of a cylinder is 1.8 cubic decimeter, and the volume of a cone with equal bottom and equal height is ().

(2) The volume of a cone is 1.8 cubic decimeter, and the volume of a cylinder with equal bottom and equal height is ().

65. There are two empty cylindrical containers and conical containers with the same bottom and height. If 6 cm high water is injected into a conical container, then all the water is poured into a cylindrical container, and the water depth in the cylindrical container is (). If 6 cm high water is injected into a cylindrical container, then all the water is poured into a conical container, and the water depth in the conical container is ().

66. On the construction site, there is a cone-shaped sand pile. The measured bottom diameter is 4m and the height is1.5m.. Each cubic meter of sand weighs about 1.7 tons, and this pile of sand weighs about () tons. (The quantity is reserved for the whole ton).

67. The approximate conical camping tent has a bottom radius of 3 meters and a height of 2.4 meters. Tent covers an area of (); The space size of the tent is ().

68. Calculate the volume of the cone below. (1) The bottom area is 9 square meters, the height is 15 decimeter, and the volume is () (2) The bottom radius is 3 decimeters, the height is 5 decimeters, and the volume is (). (3) The base diameter is 0.4m, the height is 6m, and the volume is (). (4) The base diameter and height are 12 cm, and the volume is (). 5] The height is 8 cm, the diameter of the bottom is, and the volume is ().

69. Cut a cylindrical wood with a base diameter of 6 cm and a height of 8 cm into a cone. The maximum volume of the cutting cone is ().

Cylinders and cones (4)

70. The height of the cone and the cylinder are equal, and the volume is 3.6 cubic meters, so the volume of the cylinder is () and the volume of the cone is ().

7 1, the height of cylinder and cone is equal, and the volume difference is 3.6 cubic meters, so the volume of cone is (), and the volume of cylinder is ().

72. A yurt consists of a cylinder and a cone. Its bottom radius is 3 meters, the height of the cylinder is 2 meters, the height of the cone is 1 meter, and the space occupied by this yurt is ().

73. Cut a cylindrical piece of wood into the largest cone. If the volume of the truncated cone is 2.4 cubic decimeters, the volume of the truncated cone part is ().

74. There is a gravel pile that resembles a cone. The bottom is 6.28m in circumference and1.8m in height. If each cubic meter of gravel weighs 2 tons, this pile of gravel weighs about () tons.

75, a cylinder and a cone, the bottom diameter and height are 8 cm, height is 6 cm, their volume is (). The volume of a cylinder is () times that of a cone.

76, a cylindrical barrel, 6 cents high. The ring length at the bottom of the barrel is about 15.7 decimeter. It takes at least () square decimeter to make this barrel. This bucket can hold 20 liters of water.

77, cone and cylinder height is equal, the volume of the cone is less than the volume of the cylinder ().

78. The cone and the cylinder have the same bottom and height, and the volume of the cylinder is larger than that of the cone ().

79. Cylinders and cones are equal in height. If the volume of the cone is 6 cubic meters smaller than that of the cylinder, then the volume of the cone is () and the volume of the cylinder is ().

80. Forge a cylindrical iron block into a cone with the same base and height. You can forge such a cone.

8 1, cylindrical barrel, without cover or iron sheet, with bottom diameter 12 cm and height of 35 cm. To make this bucket, you need at least () square centimeters of iron, and this bucket can hold () milliliters of water.

82. Xiaohua made a cylinder and several cones. The specifications are as follows. Pour the water in the jar into the () cone, which is just full.

83. There is a rectangular open space 20 meters long and 16 meters wide between the teaching buildings of the school. Build the largest cylindrical flower bed on this vacant lot. If the flower bed is 30 cm high, lay tiles on the outside of the flower bed, and the tile area is () square meters. Filling this flower bed requires 100 cubic meter of soil (the thickness of the flower bed can be ignored)

84. The diameter of the bottom of the cylindrical container is 10 cm, and it holds water. Immerse an iron block in water, and the water level will rise by 2 cm. The volume of this iron block is ().

85. The rectangle is 5 cm long and 2 cm wide. If you rotate on the axis of length, the resulting figure is a () shape. In this drawing, the base diameter is (), the height is (), the lateral area is () and the volume is (); If you rotate with the width as the axis, the resulting graph is a (

) shape, the bottom diameter of this figure is (), the height is (), the lateral area of this figure is (), and the volume is ().

86. The height of the conical casting with a bottom radius of 4cm and a volume of 75.36cm is ().

87. The bottom height of cylinder and cone is the same, and the volume difference is 1.2 cubic meters, so the volume of cone is (), and the volume of cylinder is ().

Cylinders and cones (5)

First, solve practical problems.

1. The cylindrical team drum has a bottom diameter of 6 decimeters and a height of 2.6 decimeters. This kind of team drum is surrounded by aluminum skin and its two bottom surfaces are sheepskin. How many square decimetres of aluminum skin does it take to make such a team drum? What about sheepskin?

2. A cylindrical mail barrel with a bottom radius of 0.6m and a height of1.5m. How many square meters does it take to make such an oil barrel? If each liter of gasoline weighs 0.85 kilograms, how many kilograms of gasoline can this oil drum hold? (The number shall be kept to one decimal place)

3. How many square meters of iron sheets are needed to make 20 ventilation pipes with a length of 2m and a nozzle diameter of 15cm?

4. A cylindrical lantern with a base diameter of 24 cm and a height of 30 cm. Stick colored paper on the bottom and sides of lanterns, at least square centimeters of colored paper?

5. How many square decimeters does it take to make an uncovered cylindrical iron drum with a height of 6 decimeters and a bottom radius of 1.8 decimeters? (Number reserved 10 square decimeter)

6. Measured from the inside, the bottom radius of the cylindrical insulated tea barrel is 3 decimeters and the height is 5 decimeters. If the water weight per cubic decimeter is 1 kg, can this thermos hold 140 kg of water?

7. Cylindrical oil drums, measured from the inside, have a bottom diameter of 40 cm and a height of 50 cm. How many square decimetres does it take to make this oil drum? If 1 liter diesel weighs 0.85kg, how many kilograms of diesel can this oil drum hold?

8. Cylindrical pool, measured from the inside, with a surface diameter of 8m and a depth of 3.5m.. Spread cement on the bottom and around the pool. What is the area of cement? How many tons of water can this pool hold at most? (weight of water per cubic meter is 1 ton)

9. A conical tent with a bottom radius of 3 meters and a height of 2.4 meters. What is the area of this tent? How big is the space in the tent?

10. On the construction site, there is a sand pile similar to a cone. The measured bottom is 4m in diameter and1.5m in height. Each cubic meter of sand weighs about 1.7 tons. How many tons does this pile of sand weigh? (Keep the whole ton as a figure)

1 1. Master Zhang wants to cut a cylindrical wood with a bottom diameter of 2 decimeters and a height of 3 decimeters into the largest cone. What is the volume of this cone?

12. There is a cone-shaped gravel pile with a bottom circumference of 25. 12m and a height of 0.6m If the gravel weight per cubic meter is 1.8 tons, how many tons does this pile weigh?

13. Make a cylindrical iron drum without a cover, each with a height of 3 decimeters and a bottom diameter of 2 decimeters. How many square meters of iron does it take to make 50 such barrels? 14. There are 10 columns in the school corridor. The radius of the bottom of each column is 4 decimeters, and the height of each column is 2.5 decimeters. Paint these columns, if the paint is 0.3 kg per square meter, how many kg does * * need to paint?

Cylinders and cones (6)

15, cylindrical barrel, height 6 decimeters. The ring length at the bottom of the barrel is about 3 1.4 decimeter. How many square decimetres does it take to make this bucket? Can this bucket hold 450 kilograms of water? (Weight per liter of water is 1 kg)

16. cylindrical beverage can with a bottom diameter of 7 cm and a height of 12 cm. Put 24 cans of such drinks into a rectangular paper box. What is the volume of this carton? How many square centimeters of cardboard does it take to make such a carton? (The overlapping part between the box cover and the bottom is calculated as 2000 square centimeters)

17, conical rice pile, bottom circumference 18.84m, height 1.5m ... If each cubic meter of rice weighs 0.85t, how many tons does this pile of rice weigh? (Numbers are reserved as integers)

18, the base of a cuboid is square, with a length of 4 decimeters and a height of 8 decimeters. It is completely immersed in a cylindrical container filled with water, and the bottom area of the container is 32 square decimeters. How many decimetres has the water surface risen?

19, conical wheat pile, bottom circumference12.56m, height10.2m.. If it is installed in a cylindrical grain depot with a bottom diameter of 4 meters, how high can it be piled?

20. The roller of the road roller is cylindrical, with a radius of 0.8m and a width of1.5m. If the roller rotates five times per minute, what is the road pressing area per minute?

2 1. How much wood does it take to cut a 6-centimeter cube into the largest cone?

22. A cylindrical barrel without a lid has a bottom diameter of 40 cm and a height of 50 cm. How many square centimeters of iron sheet does it take to make such a barrel? Can this bucket hold 60 kilograms of water? (Weight per liter of water is 1 kg)

23. Make 20 cylindrical chimneys of the same size with iron sheets, each section is 8 decimeters long and the bottom diameter is 10 cm. How many square decimetres of iron sheet do you need at least?

24, conical sand pile, the bottom circumference of 6.28 meters, 0.6 meters high. Use this pile of sand to pave a 2 cm thick road on a 4 m wide road. How many meters can you pave?

25. Fill a cylindrical cup with a bottom radius of 10 cm with water, and put a conical plumb hammer with a bottom radius of 5 cm into the water. The plumb hammer is completely immersed in the water. When the plumb hammer was taken out of the cup, the water level in the cup dropped by 0.5 cm. What is the height of the plumb hammer?

26. There is a rectangular open space 20 meters long and 16 meters wide between the teaching buildings of the school. Build the largest cylindrical flower bed on this vacant lot. If the flower bed is 30 cm high, put tiles on the outside of the flower bed. How many square meters is the tile area? How many cubic meters of soil is needed to fill this flower bed. (The thickness of the flower bed is negligible)

1, expand the side of the cylinder to get a (). The length of a rectangle is equal to () of a cylinder, and the width of a rectangle is equal to () of a cylinder. The side area of a cylinder is equal to () times ().

A pedestrian who walks 1 meter per second and a cyclist who walks 3 meters per second go south together. Then a train came, passing pedestrians in 22 seconds and cyclists in 26 seconds. Find the length of the train body.

22X - 22 = 26X - 78

The solution is X= 14.

Application questions:

There are 300 grams of sugar water with a sugar content of 20%. How many grams of sugar do you need to add to make it into syrup with a sugar content of 60%?

When summer came, my father went to the store and bought four bottles of beer. The diameter of the bottom of the bottle is 7 cm. The salesman tied four bottles of beer together. The picture on the right is a horizontal schematic diagram. How many meters of rope does it take to tie it three times?

(in the middle of the bottle)

(1) 40.5/(1-10%) = 45 (yuan)

45/( 1- 10%)=50 (yuan)

The original price of this watch is 50 yuan.

"/"is a division symbol.

(2) Percentage exercises (wrong topic highlights)

1. 66.6% and 0.58 () in descending order.

2. Percentage of businesses that indicate the following questions.

10÷6= 3÷8= 2. 1÷7= 0. 16÷8=

13.26÷ 13= 6.3÷3.5= 0.84÷0.7=

3. 100 is greater than 80 ()% 75 is less than 100 ()%.

The school/KLOC-uses 50 tons of water in October and 40 tons in September.

The water consumption in1October is ()% more than that in September, and the water consumption in September is ()% less than that in1October.

5. 150kg is ()% of 3 tons, and 20% less than () meters is 48m.

6. Add a percent sign (b≠0) after b, and the number is () 100 times.

Remove the percent sign of b%, and the number is () 100 times.

7. In sugar water with a sugar content of 30%, sugar accounts for ()% of water.

8.A number is 120, B number is 40% of A number, C number is 40% more than B number, and C number is ().

9.A number is 4/5 of B number, and B number is ()% more than A number.

10. Uncle Wang got a reward of 6000 yuan. Deduct 1000 yuan according to regulations, and pay personal income tax at the rate of 20%, and he should pay () yuan.

1 1. Danny spent a third of his money and lost the rest, leaving only $4. It turns out that he has $ ().

12. This farm tool factory produces farm tools. The original cost per piece was 80 yuan, but now the cost per piece is lower than the original 15%. How much has the cost of each piece been reduced? The formula is ().

13. The turnover of Baiyang Electric Appliance Factory was 75 million yuan in February and 90 million yuan in March. How much is the turnover in March less than that in March?

40.5 ÷ (1-10%) ÷ (1-10%) = 50 (yuan)

(2) Percentage exercises (wrong topic highlights)

1. 66.6% and 0.58 () in descending order.

2. Percentage of businesses that indicate the following questions.

10÷6= 3÷8= 2. 1÷7= 0. 16÷8=

13.26÷ 13= 6.3÷3.5= 0.84÷0.7=

3. 100 is greater than 80 ()% 75 is less than 100 ()%.

The school/KLOC-uses 50 tons of water in October and 40 tons in September.

The water consumption in1October is ()% more than that in September, and the water consumption in September is ()% less than that in1October.

5. 150kg is ()% of 3 tons, and 20% less than () meters is 48m.

6. Add a percent sign (b≠0) after b, and the number is () 100 times.

Remove the percent sign of b%, and the number is () 100 times.

7. In sugar water with a sugar content of 30%, sugar accounts for ()% of water.

8.A number is 120, B number is 40% of A number, C number is 40% more than B number, and C number is ().

9.A number is 4/5 of B number, and B number is ()% more than A number.

10. Uncle Wang got a reward of 6000 yuan. Deduct 1000 yuan according to regulations, and pay personal income tax at the rate of 20%, and he should pay () yuan.

1 1. Danny spent a third of his money and lost the rest, leaving only $4. It turns out that he has $ ().

12. This farm tool factory produces farm tools. The original cost per piece was 80 yuan, but now the cost per piece is lower than the original 15%. How much has the cost of each piece been reduced? The formula is ().