Two 5th grade math problems, know how to !! quickly

Question 2 2*(10*8+10*3+8*3)-24=244 square meters.

244-8*10=164 square meters (excluding the roof part) 244*kg.

The first question is wrong.

It should be this: A, B, and C type a manuscript together. A and C typed three-quarters of the manuscript together, B and C typed two-thirds of the manuscript, and each of them typed as much.

C: Three-quarters + two-thirds - 1 = 5/12

Then bring in one minus A: one-third B: one-quarter.

Done, look.

1.Solution: Because A, B, and C type a manuscript together, that is, 1 and A + C = 3 4, B + C = 2 3

So B = 1-3 4 = 1 4, A = 1-2 3 = 1 3 so C = 1-1 3-1 4 = 5 12

2.Solution: s=2 (10 8 + 10 3 + 8 3) = 268 (square meters) to paint area (excluding floor): 268-10 * 8-24 = 164 (square meters of paint): 164 kg).

The second 10x8+(10x3+8+3)x2-24 calculation result is multiplied by how many kilograms of paint are bought.

C 3 4 + 2 3 a 1 = 5 12

A 3 4-5 12 = 1 3

B 2 3-5 12=1 4 The slash is the fractional line.

1 A cylinder and a cone are equal in height at the bottom, and if their volumes differ by 32 cubic decimeters, then the volume of the cone is ( ) cubic centimeters.

2.The surface area of a cube with an edge length of 6 decimeters is ( ) square decimeters, and it is cut into the largest cone, and the volume of this cone is ( ) cubic decimeters.

3.The sum of the volume of the cylinder and the cone of equal height is 28 cubic meters, and the volume of the cylinder is ( ).

4. The bottom radius of a cone is the radius of the bottom surface of a cylinder, and the ratio of the height of the cylinder to the height of the cone is 4:5, so the volume of the cone is the volume of the cylinder

5. The radius of the bottom surface of a cylinder is 2 decimeters, and the area of the side of the cylinder is a square decimeter, what is the volume of this cylinder in cubic decimeters?

6. There is a cylindrical grain storage barrel, the volume is cubic meters, the depth of the barrel is 2 meters, after filling this barrel with rice, the rice is piled into a high rice cone on top How many cubic meters is the volume of rice in this grain storage barrel? (Keep two decimal places).

7. A 2-meter-long cylindrical piece of timber with a cross-sectional radius of 10 cm, sawn vertically along the diameter of the cross-section, divided into two equal pieces, what is the volume and surface area of each piece?

8 When a cylinder is machined into a cone of the same height as its base, the ratio of the volume of the cylinder to the volume of the removed part is (

9. Cast 4 cylinders of the same size into cones of equal bottom and height, which can be cast ( ).

10. A section of cylindrical logs is processed into a cone of equal height and equal bottom, and part of the volume is cylindrical ( ) is conical ( ).

11 There is a round steel with a length of 20 cm and a radius of 2 cm, and a conical hole with a depth of 4 cm and a bottom radius of 2 cm is drilled at each end of it to make a part.

12 What happens to a cylindrical bucket with a height of 3 decimeters and a bottom diameter of 20 centimeters filled with water, and an iron cone with a bottom diameter of 18 centimeters and a height of 15 centimeters is placed in the water? The result?

13.The bottom radius and height of a cone are 3 cm, and its volume is ( ).

14.3 cylindrical ingots, which can be cast into conical ingots of the same height as the bottom

15 The ratio of the circumference of a cylinder to a cone, the circumference of the base is 2 3, the ratio of their volumes is 5 6, and the simplest integer ratio of the height of the cone to the cylinder is (

16.There is a pile of conical rice on the threshing floor, the bottom circumference is meters, the height of the rice pile is how many meters?

Question 1: 18 200 = 18 200 = 9 10023 200 = 23 200 = 23 200

There are two questions in the second question... The choice is yours:

1. (120 + 120) 3 3 + 120 360 kilometers The first distance is not met, the second distance is 120 kilometers after the encounter, the two 120 add up and divide by 3 is the sum of the speed of the two cars, multiply 3, it is the two cars before the meeting, plus the middle 120 is the distance between the two places.

[(6 2)+2] 60 pcs wooden box (300-2 60) 6 30pcs carton.

2 cartons, 1 wooden box, 6 cartons, 3 wooden boxes, 300 crystal balls can be packed in (3+2) wooden boxes, then each wooden box contains 60 crystal balls; After removing the 300 crystal balls and putting them in 2 wooden boxes (120 pieces), the remaining 180 are packed in 6 cartons, so each carton contains 30 pieces.

1. The distance traveled by the two cars in the second 3 hours is 120+120=240km, and the average speed is 80km/h.

At the beginning, 3 hours = 80 * 3 = 240km, at this time the two cars are still 120km apart, so the answer is 360km

2. If each wooden box is packed x pcs, then each carton is x 2, 2x + 3x = 300, x = 60

60 pcs in wooden box and 30 pcs in carton.

1.Let the sum of the speeds of cars A and B be x km h, and according to the title, (3+3)x-120 2=3x+120

6x -240=3x+120

6x-3x=120+240

3x=360

x = 120 The sum of the speed of the two vehicles is 120km h

The distance between the two places is 3 120+120=480km2If a carton contains x crystal balls, then a wooden box contains 2x crystal balls, and 6x+2x2x=300 according to the title

6x+4x=300

10x=300

x=30 30 crystal balls per carton and 60 crystal balls per wooden box.

(1) From the first time 120 kilometers to the second time 120 kilometers apart, in these 3 hours, car A and B 2 traveled a total of 240 kilometers, so the sum of the speed of car A and B 2 is 240 3 = 80 km hours.

Therefore, the distance between AB is 80 * 3 + 120 = 360 kilometers (2) If there is no carton for x crystal balls, then there is no wooden box for 2x, a total of 300 balls, and the equation can be listed according to the question.

6x+2*2x=300, so 6x+4x=300, get x=30 so there is no carton for 30, and wooden box for 60.

1. According to the title, it can be seen that 3 hours of driving 2x120, so the sum of the speed of the two cars is 80 kilometers per hour.

Therefore, the distance between the two places is 3x80+120=360 km.

2. You can think of the wooden box as two cartons, so 10 cartons put 300 balls, one carton put 30 balls, and the wooden box put 60 balls.

*2 = 240 (km) 240 + 120 = 360 (km 2 = 3 (pcs) (6 cartons are equivalent to three wooden boxes) 3 + 2 = 5 (pcs) (5 wooden boxes in total).

300 5 = 60 (pcs) (60 pcs per wooden box).

60 2=30 (pcs) (30pcs per carton).

(1) Let the speed of A be xkm h and the speed of B be ykm h, and the total distance is skm3(x+y)=120+120 to obtain x+y=80s=3(x+y)+120 s=360

2) Set a carton for x, then a wooden box for 2x 2*2x+6x=300 x=30, so the carton is 30 and the wooden box is 60

1. A and B are 360 kilometers apart.

300 balls in a carton. 60 and 30 each

1.The speed of A and B is 120 3 = 40km h, so the distance between A and B is 40 times 3 times 2 + 120 = 360km.

2.Let each have x,y, then y=2x,2y+6x=300, and the solution is x=30, y=60.

s=120+120/2=180km

2.Let each carton be x pcs, then 2 * 2x + 6x = 300 solution: x = 30 So each wooden box is 60 pcs, and each carton is 30 pcs.