Xiao Ming has 8 pieces of RMB with 5 yuan and 2 yuan in total. How many pieces of RMB with 2 yuan and 5 yuan

Xiao Ming has 8 pieces of RMB with 5 yuan and 2 yuan in total. How many pieces of RMB with 2 yuan and 5 yuan

Let 5-ary have X sheets, then 2-ary have (8-x) sheets. The formula 5x + 2 (8-x) = 22 gives x = 2, so there are 2 sheets of 5-ary and 6 sheets of 2-ary

Xiao Ming has several pieces of RMB 1 yuan, 2 yuan and 5 yuan each. How many different ways do you want to take out 10 yuan? List them out. There are good answers and a reward
Xiao Ming has several pieces of RMB of 1 yuan, 2 yuan and 5 yuan. How many different ways can he take out 10 yuan?
List them
There is a good answer and a reward

First: ten one yuan tickets
Second: 5 pieces of 2 yuan
Third: two five yuan tickets
Fourth: 2 1 yuan + 4 2 yuan
Fifth: 4 1 yuan + 3 2 yuan
Sixth: six 1 yuan + two 2 yuan
Seventh: 8 pieces of 1 yuan + 1 piece of 2 yuan
Eighth: one 2 yuan + three 1 yuan + one 5 yuan
Ninth: two 2 yuan + one 1 yuan + one 5 yuan
Tenth: five 1 yuan plus one 5 yuan

Mr. Qin has 20 pieces of RMB with a face value of 5 yuan and 10 yuan. It is known that there are two kinds of RMB with a total value of 160 yuan. How many pieces of RMB with a face value of 5 yuan and 10 yuan?

According to the stem analysis, we can get: (10 × 20-160) / (10-5) = 40 / 5 = 8 (sheets) 20-8 = 12 (sheets) a: 8 sheets for 5 yuan, 12 sheets for 10 yuan

Car a starts to catch up with car B 7m ahead at an acceleration of 2m / S2. Car B is driving at a constant speed of 10m / s. After 5S, car B accelerates at an acceleration of 1m / S2, and car a's acceleration remains unchanged. Finally, car a catches up with car B. try to find out 1. What's the speed of car a when car a catches up with car B? 2. What's the total displacement of car B before catching up with car B

1. It takes T seconds for car a to catch up with car B
1/2*a1t^2=5X10+[10(t-5)+1/2*a2(t-5)^2]+7
a1=2,a2=1
The solution is t = 13
So when car a overtakes car B, the speed of car a is v = a1t = 2m / S ^ 2x13s = 26m / s
2. The total displacement of car B is 5x10 + [10 (T-5) + 1 / 2 * A2 (T-5) ^ 2] = 162m

1. Given x ^ 2-3x-1 = 0, find x ^ 2 + (1 / x ^ 2)
2. Observe the following equation:
16-1=15；25-4=21；36-9=27；49-16=33；……
Using natural number n (n ≥ 1) to express the above series of equations, the law reflected is______
3. Given that 2 ^ 8 + 2 ^ 10 + 2 ^ n is a complete square number, find the value of n
4. Let a.b.c.d be certificates, and M = a ^ 2 + B ^ 2, n = C ^ 2 + D ^ 2, then m * n can be expressed in the form of the sum of the squares of two integers, which is the reason
5. The L-long wire is surrounded into a rectangle. When the length of the two adjacent sides is respectively, the area of the rectangle is the largest
Do as much as you can
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Happy Christmas to you

1. X1 = (3 + radical 13) / 2, X2 = 3-radical 13) / 2
X ^ 2 + (1 / x ^ 2) = 8 / 11 + 3 radical 13 + (11 + 3 radical 13) / 8 or 8 / 11-3 radical 13 + (11-3 radical 13) / 8
2.(n+3)^2-n^2
L / 4, L / 4, a square is a special rectangle

As shown in the figure, a uniform board with mass of M = 2kg and length of L = LM is placed on a horizontal table with enough length, and the initial speed is zero. A small block with mass of M = 1kg is placed at the leftmost end of the board, and the dynamic friction coefficient between the small block and the board is μ 1 = 0.2. A horizontal light rope with enough length is connected to the small block, and the rope crosses the fixed pulley (the distance between the rope and pulley) at the edge of the table The distance between the board and pulley is long enough (g = 10m / S2), regardless of friction (1) If the board is fixed, pull down the rope with constant force F = 4N, and calculate the speed V1 when the small block slides away from the board; (2) if the board is not fixed, and the board and the desktop are smooth, someone still pull down the rope with constant force F = 4N, and calculate the speed V2 when the small block slides away from the board; (3) if the board is not fixed, and there is friction between the board and the desktop, someone pulls down the rope with constant speed v = 1m / s, in order to make the board stable The block can slide out from the right end of the board, and the dynamic friction coefficient μ 2 between the board and the table top can be calculated

(1) By Newton's second law: F - μ 1mg = ma & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; a = 2m / S2 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; by kinematic formula: V12 = 2Al & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; V1 = 2m / S & nbsp; & nbsp; &By Newton's second law: F - μ 1mg = MA1 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp;, A1 = 2m / S2 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp;, A2 = 1m / S2 from: μ 1mg = ma2 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; The displacement of the wooden board: the displacement of the wooden board: the displacement of the wooden board: the displacement of the wooden board: the displacement of the wooden board: the displacement of the wooden board: the displacement of the wooden board: the displacement of the wooden board: the displacement of the wooden board: the displacement of the wooden board: the displacement of the wooden board: the displacement of the wooden board: the displacement of the wooden board: the displacement of the wooden board: the displacement of the wooden board: the displacement of the wooden board: the displacement of the wooden board: the displacement: the displacement of the displacement of the wooden board: the displacement: the displacement of the displacement of the wooden board: the displacement of the displacement of the displacement of the wooden board: the displacement of the displacement of the displacement of the wooden board: the displacement of the displacement of the displacement of the displacement of the wooden board: the displacement of the displacement of the displacement of the displacement of the displacement of the wooden board: the displacement of the displacement of the displacement of the displacement of the displacement of the displacement of the displacement of the displacement of the displacement of the displacement of the displacement of the displacement/ S. & nbsp; &(3) let the sliding time of the block on the board be t, the speed of the board is just v when the block slides to the right end of the board, and the dynamic friction coefficient between the board and the table is μ 2. For the board: [μ 1mg - μ 2 (M + m) g] MT = V & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; for the block: vt-v2t = L & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; the solution is: MV μ 1mg - μ 2 (M + M) g = 2lv & nbsp; & nbsp; & nbsp; &The solution is: μ 2 & nbsp; = 2 μ 1mgl-mv22 (M + m) gl = 130. In order to make the block slide out from the right end of the plate, μ 2 & gt; 130; Answer: (1) the speed V1 of the small block sliding away from the board is 2m / S; (2) the speed V2 of the small block sliding away from the board is 22s; (3) in order to make the block slide out from the right end of the board, the dynamic friction coefficient μ 2 between the board and the desktop must be greater than 130

How many kilos and Jin is one ton?

Hello!
1 ton (T) = 1000 kg (kg) = 20 kg / kg = 2000 kg / kg

When 3 / 5 of the volume of the block is immersed in water, the indication of the spring dynamometer is exactly as follows: (1) what is the density of the block? (2) if the block is removed from the spring dynamometer and gently put into the water, how much vertical downward pressure can be applied to the block to make it completely immersed in water? (g = 10N / kg)

(1) When 3 / 5 of the volume of the block is immersed in water, the indication of the spring dynamometer is just zero, which indicates that the floating of the block has the following characteristics:
F = g wood
That is, ρ water GV row = ρ wood GV wood
So ρ wood = ρ water V row / V wood
=ρ water (3 / 5) V wood / V wood
=0.6g/cm^3
The volume of wood block is:
V wood = g / ρ wood g = 6 / (0.6 × 10 ^ 3 × 10) = 10 ^ - 3M ^ 3
(2) It can be seen from the meaning of the title that in this case, the wood block is in equilibrium under gravity, buoyancy and pressure, so it has the following formula: F floating ˊ = G + F
That is, f = f floating ˊ - g = ρ water GV draining ˊ - G
=10^3 ×10×10^-3-6
=4N

The side length of a cube is a cm, and its surface area is s cm. Write the relationship between the surface area s of a cube and the side length a, and the side length a changes from 1 cm to 10 cm s

S=6a*a

In the past, on the floor of the elevator moving at a constant speed, there was a light spring which was in the state of elongation, and the wooden block a with a certain mass was still on the floor, as shown in the figure. Now it is found that the wooden block is suddenly pulled to the right by the spring, so it can be judged that the following statement is correct ()
A. The elevator may decelerate upward and the block is weightless. B. the elevator must accelerate upward and the block is overweight. C. the elevator may accelerate upward and the block is overweight. D. the elevator must have downward acceleration and the block is weightless

When the elevator is stationary, the static friction of the floor to the object is balanced with the elastic force of the spring, and the static friction may be less than or equal to the maximum static friction. When the elevator has downward acceleration, it will inevitably reduce the positive pressure of the object on the floor, which also reduces the maximum static friction force. At this time, the maximum static friction is less than the electric force