Does anyone have 1000 questions in logic and mathematics

Question conditions: Only one person told the truth.

It was noted that the statements of A and B were contradictory.

Among them, there must be one true and one false, and it is impossible to be true and false.

Then the words of C must be sooner, and those who are slow are falsehoods.

Reverse deduction can be obtained to be the chair of C repair.

Further, A has spoken a false and B has told the truth.

The chair in the classroom was broken, and the next day I went to school and was sleepy, and the teacher found that the chair had been repaired. It was understood that the chair was repaired by one of the three people, A, B, and C, and the teacher found these three people.

A said, "It was done by B." ”

B said, "I didn't do it." ”

C said, "I didn't do it." ”

Upon investigation, only one of the three told the truth. Please use reasoning to find out who built the chair?

Reasoning with hypothetical premises to rule out contradictions.

Suppose A tells the truth。That is, it is done by b. Then: C is a lie, and the opposite refers to C doing it. Contradictions,The assumption is not true

Suppose B tells the truth。That is, it is done by A or C. Then:

A is a lie, which means that B did not do it; Wang Shu C is a lie, and the reverse refers to the fact that it is done by concealing and C. The assumption is true,c do

Suppose C tells the truth。That is, A or B did it. then: A is a lie, which means that B did not do it; b is a lie, and the opposite is that b did it. Contradictions,The assumption is not true

To sum up: it is done by C.

My Thoughts: Observe the white pieces of the five figures.

In order, they are axisymmetric, center-symmetric, axis-symmetrical, center-symmetric, and axisymmetric.

So the next white piece is centrally symmetrical, choose A

I count the white seeds: the previous row has 10, 12, 13, 15, 12, a12, b17, c13, d13

Look at the trend of increase and decrease: increase first and then decrease, so choose the minimum value of ABCD A

The brain hole is a bit big, and it's not clear for the time being

Summary. Dear, send me your title.

Dear, send me your title.

Shengsheng is an investor in the financial market . People in the financial market can buy and sell ** . People can make a profit by selling at a low price and at a high price.

Initially, Victory had $15,000 in cash. When ** was worth $342 per share, he bought 30 shares of Horst Co. Victory later sold 20 shares when the stock price reached $509.

And when the stock price fell back to $420 , Victory lost another 25 shares . Q: How much stake and cash will Victory own after these transactions are completed?

The answers are: a) 4, US$420 in cash, US$10, US$580** b) 4, US$420 in cash, US$13 , US$13 in 920** c) 1, US$1 in cash, US$13 ,920 ** d) 4, US$420 in cash, US$14 in 700**.

Dear, the answer is D

The process can be calculated in three stages.

Pythagorean theorem. The square of the right triangular hypotenuse is equal to the sum of the squares of the other two sides. For example, for the triangular shape shown in the figure below, a b = c2 .

Xiao Ming planned to run along the path shown in the map . A circle consists of going from A to B, B to C, C to D, and D back to A. The distance from A to B is 400m, the distance from C to D is 300m, and the distance from A to C is 200m.

if xiao ming ran along this road twice , how far would he run in total ?

Dear, the answer is 3016

You can see it.

This open root number is approximately equal to.

All cars manufactured by Car Motors have a key mode 05 % were defective. 80 percent of vehicles with this defect are repaired immediately at the factory.

The remaining 20% was ignored and delivered to retail stores. In 2020, SEG Motors exported 30,000 vehicles to China. Calculate how many defective vehicles were shipped to China in 2020.

The answer is empty

It's a choice.

Right. Okay, I'll do the math.

30 cars.