A section of cuboid wood is one meter long. If it is sawn two centimeters short, its volume will be reduced by 20 cubic centimeters. What is the original volume of this section of wood?

What is the base area of wood
20 △ 2 = 10 (square centimeter)
1m = 100cm
What is the original volume of wood
10 × 100 = 1000 (cm3)

How many cubic centimetres is the volume of the largest cylinder made of a cubic timber with an edge length of 10 cm? How many cubic centimetres is the timber to be removed

3.14*5*5*10=785
10*10*10-785=215

There are 49 workers in Tongxing toy factory who produce toy motorcycles. Each worker can produce 12 car bodies or 18 tires per hour. If they want to produce car bodies and tires (one car body with two wheels), how many workers should produce car bodies and how many workers produce tires? I think this problem will embarrass many people
Correct answer, integral is yours, come on, please help me, I can't turn this question

Worker efficiency ratio = 12:18 = 2:3
Demand ratio = 1:2
Then the yield ratio = (3 × 1): (2 × 2) = 3:4
Then the number of car body production = 49 × 3 / 9 = 21 (person)
Number of people producing wheels = 49 × 4 / 49 = 28 (people)
The car body is 21 × 12 = 252 and the wheel is 28 × 18 = 504
Body production 252: wheel production 504 = 252:504 = 1:2

The circumference of a rectangle is 8.4 meters, the length is 2.9 meters, and the width is several meters?

8.4 △ 2-2.9 = 1.3m

1\3+1\6+1\10+1\15+1\21+1\28+1\36+1\45+1\50+1\55
Please write the process clearly and don't omit it

The original formula = 2 * (1 / 6 + 1 / 12 + 1 / 20 + 1 / 30. + 1 / 110 + 1 / 100) = 2 * [(1 / 2-1 / 3) + (1 / 3-1 / 4) + (1 / 4-1 / 5) + (1 / 5-1 / 6) +. + (1 / 10-1 / 11) + 1 / 100] = 2 * [1 / 2-1 / 11 + 1 / 100] eliminate the intermediate term = 2 * 461 / 1100

It takes 40 seconds for a train to cross a 440 meter bridge and 30 seconds to cross a 310 meter tunnel at the same speed M / s Rice?

(1) The speed of the train is (440-310) / (40-30), = 130 / 10, = 13 (M / s); (2) the body length is: 13 × 30-310, = 390-310, = 80 (m). So the answer is: 13 m / s, 80 M

As shown in the figure, a large rectangle is made up of seven identical small rectangles. It is known that the perimeter of a large rectangle is 34 cm. Find the length and width of a small rectangle
5x＝2y
2 (5x + X +) = 34 is this the case? If so
5x＝2y
2（5x＋x＋y）＝34

34 / 2 = 17 cm, because there are seven small cuboids, the length and width of a large cuboid are 10 cm and 7 cm, or 11 cm and 6 cm respectively. There are eight ways to divide the length and width of each cuboid by 7, which is the length and width of a small rectangle
2.5X=2Y,Y=5/2X
2(5X+X+Y)=34
2(5X+X+5/2X)=34
10X+2X+5X=34
17X=34
X=2

In the given sequence {an}, A1 = 1, and the point P (an, a (n + 1)) (n belongs to n) is on the straight line X-Y + 1 = 0, if the function f (n) = 1 / (n + A1) + 1 / (n + A2) + 1 / (n + a3) + +1 / (n + an) (n ∈ n, and N ≥ 2), find the minimum value of function f (n);

Point P (an, a (n + 1)) (n belongs to n) on the straight line X-Y + 1 = 0, in the sequence of an + 1-an = 1 {an}, A1 = 1. D = 1, so an = a1 + (n-1) * 1 = n  f (n) = 1 / (n + A1) + 1 / (n + A2) + 1 / (n + a3) + +1 / (n + an) (n ∈ n, and N ≥ 2) = = > F (n) = 1 / (n + 1) + 1 / (n + 2) + 1 / (n + 3) + +1/(n+n)=1/(n+1)+1/...

The taxi charging standard of a taxi company is: 5 yuan for a distance of 0-3 km; for the part more than 3000 meters (less than 1 km, it is calculated as 1 km), each kilometer
The fee is 1.5 yuan. Dad traveled 6 kilometers from land a to land B. how much yuan should dad pay?

6-3=3
5 + 3 * 1.5 = 9.5 (yuan)

When a rectangular frame is drawn into a parallelogram, its perimeter and area will not change?
What about perimeter and area?
Why?

Perimeter unchanged, smaller area
The reason is very simple, the parallelogram area formula, the bottom * height, the pulling process must make the height drop, further discussion needs to use trigonometric function, here only needs the perceptual understanding

A section of cuboid wood is one meter long. If it is sawn two centimeters short, its volume will be reduced by 20 cubic centimeters. What is the original volume of this section of wood?