It s hard to die, oh master, ask for help The last one, can such a question be lengthened

1.Brain teaser fun brain teaser fun = (integer answer), no solution.

2.Brain teaser fun brain teaser fun = (integer answer), no solution.

3.Brain teaser fun brain teaser fun = (integer answer), no solution.

4.Brain teaser fun Brain teaser fun = (integer answer), 1:

5.Brain teaser fun brain teaser fun = (integer answer), no solution.

6.Brain teaser fun brain teaser fun = (integer answer), no solution.

7.Brain teaser fun Brain teaser fun = (integer answer), 1:

8.Brain teaser fun Brain teaser fun = (integer answer), 1:

1.Brain teaser fun Brain teaser fun = (integer answer) , 1:

2.Brain teaser fun Brain teaser fun = (integer answer) , 1:

3.Brain teaser fun Brain teaser fun = (integer answer), no solution.

4.Brain teaser fun Brain teaser fun = (integer answer) , 1:

5.Brain teaser fun Brain teaser fun = (integer answer) , 2:

6.Brain teaser fun Brain teaser fun = (integer answer), no solution.

7.Brain teaser fun Brain teaser fun = (integer answer) , 2:

1.Brain teaser fun Brain teaser fun = (integer answer) , 1:

Analysis: After 10 times, the remaining toys are exactly 20, which cannot be understood as: sell half, add 20, and leave 20, otherwise it is 0 before adding, which doesn't make sense; It can only be understood as:

There were 40 of them, half of them were sold, and 20 were left; In this way, there were 40 original toys, half of them were sold, 20 were left, 20 were added, and 40 were added, and the cycle repeated.

Solution: From the analysis, this question is a repeated cycle of questions, so the original toys: 20 12 = 40 (pieces), answer: the original toys in the toy store 40

Remove 3 first, and calculate the equivalent voltage UO and the equivalent resistance req between ABs.

Only consider the voltage source, the current source is equivalent to the open circuit, the series equivalent of the 2V voltage source and the 2 resistors is 1A current source and 2 resistors in parallel, the same method obtains the parallel 2A current source and 4 resistors in parallel, the current sources are combined to obtain the 3A current source, and the 2 resistors and 4 resistors are equivalent to 4 3 resistors, so the final equivalent is that the 4V voltage source is connected in series with the 4 3 resistors. So uo'=4v。

Only the current source is considered, the voltage source is equivalent to a short circuit, and the 10 resistance can be ignored, UO''=-1*2/3=-2/3v。

So the equivalent voltage uo=uo'+uo''=10/3v。

Equivalent resistance req = 2 4 + 2 3 = 4 3 + 2 3 = 2 .

If the 3 resistor is added to the equivalent circuit to form a loop, we can see that i=uo (req+3)=(10 3) (2+3)=2 3a.

Exclusion method, this reaction is a reversible reaction, the initial concentration of x2, y2, z is, assuming that x2 and y2 are completely reacted, then the maximum concentration of z at this time is, but because the reaction is a reversible reaction, x2 and y2 cannot react completely, so d is excluded; Assuming that Z completely reacts to generate X2 and Y2, then the concentrations of X2 and Y2 are respectively, and the reaction can not be completely reacted, so B and C are excluded, so A. is selected

Let the side length of the vertical old wall be x, and the parallel wall should be 30-3x.

Area = -3x 2-3x

3(x^2-10x+25)+75

3(x-5)^2+75

When x = 5, the maximum area is 75 square meters.

Let me come: according to the triangle any two sides are greater than the third side, there are Pa + PB > AB, Pa + PC > AC, PB + PC > BC, the three forms are superimposed and simplified, that is.