There are upper, middle and lower layers on the bookshelf. A total of 192 books have been put on the bookshelf. First, take out as many books from the upper layer as the middle layer and put them on the middle layer. Then take out as many books from the middle layer as the lower layer and put them on the lower layer. Finally, take out as many books from the lower layer as the upper layer and put them on the upper layer. At this time, the books on the three layers are just the same?

There are upper, middle and lower layers on the bookshelf. A total of 192 books have been put on the bookshelf. First, take out as many books from the upper layer as the middle layer and put them on the middle layer. Then take out as many books from the middle layer as the lower layer and put them on the lower layer. Finally, take out as many books from the lower layer as the upper layer and put them on the upper layer. At this time, the books on the three layers are just the same?

Finally, the upper, middle and lower levels each have 192 △ 3 = 64 (copies). Finally, take out as many books left from the lower level as those left from the upper level and put them on the upper level. This is the same number of books on the three levels. It shows that the lower level gives the upper level 64 △ 2 = 32 (copies); the lower level does not give the upper level 64 + 32 = 96 (copies); the lower level has 96 △ 2 = 48 (copies); the middle level does not give the lower level 192-32-48 = 112 (copies); the middle level has: Answer: there are 88, 56 and 48 books on the upper, middle and lower shelves

There are upper, middle and lower layers on the bookshelf. A total of 192 books have been put on the bookshelf. First, take out as many books from the upper layer as the middle layer and put them on the middle layer. Then take out as many books from the middle layer as the lower layer and put them on the lower layer. Finally, take out as many books from the lower layer as the upper layer and put them on the upper layer. At this time, the books on the three layers are just the same?

Finally, the upper, middle and lower levels each have 192 △ 3 = 64 (copies). Finally, take out as many books left from the lower level as those left from the upper level and put them on the upper level. This is the same number of books on the three levels. So, the lower level gives the upper level 64 △ 2 = 32 (copies); the lower level does not give the upper level 64 + 32 = 96 (copies); the lower level originally has 96 △ 2 = 48 (copies)

There are upper, middle and lower layers on the bookshelf. A total of 192 books have been put on the bookshelf. First, take out as many books from the upper layer as the middle layer and put them on the middle layer. Then take out as many books from the middle layer as the lower layer and put them on the lower layer. Finally, take out as many books from the lower layer as the upper layer and put them on the upper layer. At this time, the books on the three layers are just the same?

Finally, the upper, middle and lower levels each have 192 △ 3 = 64 (copies). Finally, take out as many books left from the lower level as those left from the upper level and put them on the upper level. This is the same number of books on the three levels. So, the lower level gives the upper level 64 △ 2 = 32 (copies); the lower level does not give the upper level 64 + 32 = 96 (copies); the lower level originally has 96 △ 2 = 48 (copies)

A flywheel rotates around the shaft at an angular velocity of ω 0, and the moment of inertia of the flywheel to the shaft is J1,
Another stationary flywheel is suddenly meshed on the same shaft. The moment of inertia of the flywheel to the shaft is twice that of the former=__________

The angular momentum of the two flywheels is conserved, the initial angular momentum P1 = J1 * W0 (because the other flywheel is stationary, so the angular momentum is zero, just calculate the first one). After meshing, let the common angular velocity be w, the angular momentum be P2 = (J1 + J2) * w = 3J1 * W, because P1 = P2, w = 1 / 3wo can be obtained

In the known arithmetic sequence an, the sum of the first n terms is Sn, and A4 = - 3, S10 = 0. What is the minimum value of Sn

Because an is equal difference, so S10 = 10a4 + 15d = 0, so d = 2
And A4 = a1 + 3D, so A1 = - 9
So Sn = - 9 + n * (n-1) d
Because n is a positive integer, when n = 5, the minimum value of Sn is - 25

The speed of a car running along a flat and straight road is 36km / h. The acceleration obtained after braking is 4m / S2, which can be calculated as follows: (1) the speed at the end of 3S after braking; (2) the speed at half the distance from braking to stopping

(1) 36km / h = 10m / s. according to the speed time formula, the time required for the vehicle braking speed to decrease to zero is t = 0 − v0a = − 10 − 4S = 2.5s ＜ 3S. Then the speed at the end of 3S after braking is zero. (2) if the speed at half of the sliding distance is V, then V2 − V02 = 2A · X20 − V2 = 2A · X2, v = V022

Xiao Li and Xiao Lan play rope skipping. Xiao Li jumps four times as many as Xiao Lan. Xiao Lan jumps 39 times as many as Xiao Li. How many do Xiao Li and Xiao Lan jump?
Answer with arithmetic and write the meaning
Xiaoli jumps more than Xiaolan, and the number of Xiaolan jumps is three times, 39 (4-1) = 13, 13 × 4 = 52, so Xiaoli jumps 52, and Xiaolan jumps 13. Do you have a good formula?

Xiaolan jumped 39 / 3 = 13
Xiaoli jumped 13 + 39 = 52

A mathematics problem about triangle in the first day of junior high school
1. The base of an isosceles triangle is 5cm long. The middle line of a waist divides the circumference of the triangle into two parts. The difference between the two parts is 3cm. Find the waist length of the triangle

The difference between the bottom and the waist is 3cm, while the bottom is 5cm
1: The bottom edge is 3cm longer than the waist edge, and the waist length is 5-3 = 2cm
According to the triangle trilateral relation theorem, the trilateral length is 5,2,2,2 + 28, so 2 holds
The waist length of this triangle is 8cm

As shown in the figure, the line segments a, B and C are known. Use a compass and a ruler to draw the line segments so that they are equal to a + 2b-c1 a + B line segments a = -- B = -- C = --

Method:
(1) OL was used;
(2) On the ray ol, OA = a, ab = B, BC = B are successively intercepted
(3) Cut CD = C on the line Co, and the line od is the line

Please use the system of linear equations with 2 variables to solve the problem. The complete process and correct answer are urgently needed,
A new batch of goods are ready for sale. If you sell them at a 20% discount, they can be sold out in 10 days and make a profit of 1000 yuan. If you sell them at a 7.5% discount, they can be sold out in 8 days and make a profit of 8000 yuan. It costs 100 yuan to store them for one day. What are the purchase price and total budget price of these goods?
[Note: please use a system of linear equations with 2 variables or a system of linear equations with 3 variables,]

Let the purchase price be x and the total pre-sale price be y
0.8*y-10*100-1000=x
0.75*y-8*100-800=x
The solution is: x = 4400
y=8000
Note: if the data is wrong, it should be the profit of 7.50% discount, otherwise the result is negative. If you change 8000 to 800, you can get the above result, and the process is correct