Primary School Review Guide, Mathematics, Have Wood and Answers? It s better to explain. Myself.....

This type of plagiarism is done using the hypothetical method. (If you think about it carefully, it is the same cage of chickens and rabbits) assumes all.

The questions are all done. Assuming that everything is done correctly, 30*5=150 points are awarded.

But the actual score is 122 points, the difference is 150-122 = 28 points, then there must be a wrong question, each wrong question is less than 5 + 2 = 7 points, so a total of 28 7 = 4 questions, so a total of 30-4 = 26 questions are correct.

You think: If Xiao Ming Bai does everything right, then he will score 150 points.

But he zhi

I only had to DAO to 122 points, and there were 28 points left to go to the specialty.

In other words, there are some questions that he not only did not do correctly, but also did it wrong, so that there is a difference of 7 points between one correct question and one wrong question.

So he got 4 questions wrong. Do 26 questions correctly.

I hope it helps you.,You can ask for it.。。

ps I solved it with the idea of elementary school.,Of course, you can also do it with equations.。。

If you get all the questions right, 5 30 = 150 points, 1 wrong question will get 5 + 2 = 7 points, the number of wrong questions (150-122) 7 = 4 questions, and the number of correct questions 30-4 = 26 questions.

Use the solution equation to set: If Xiao Ming answers the x question correctly, he answers the wrong (30-x) question.

Because each correct question is worth 5 points, Xiao Ming's correct version score is 5x. Because 2 points are deducted for each question he gets wrong, Xiao Ming's score for his incorrect answer is 2 (30-x).

Hence the columnist equations:

5x-2（30-x）=122

5x-60+2x=122

7x=182

x=26The final answer is 26 questions answered correctly.

The landlord's 24 questions are wrong.

Simple equations should have been learned in primary school.

Do x right, then wrong (30-x).

5x-(30-x)*2=122

x=26 got 26 questions right.

You can solve the equations, and list the equations according to the requirements of the topic

If you get x questions right, you get 30-x questions wrong. So there is 5x—2(30—x) 122

7x＝182

x 26 got 26 questions right.

Solution: Set Xiao Ming to do a total of x questions correctly.

5x-2（30-x）=122

x=26Answer: Xiao Ming got a total of 26 questions right.

This question is a bit ambiguous, if you answer incorrectly only 2 points, you can actually count the number of dao questions that answer incorrectly, and a correct answer is back to 5 points, then if you answer all correctly, the full score of the whole answer sheet is 150And he only got 122It means that he answered incorrectly (150-122) 2=14 questions, so he finally answered 16 questions correctly, because the full score of a question is 5 points, and only 2 points are deducted for answering incorrectly, so 3 points for each of the 14 questions he answered incorrectly are in vain, so he will get (16*5)+(14*3)=122 points in the end.

And if you answer one incorrectly, not only will you not be scored, but you will also be deducted 2 points, which means that you will deduct 7 points for the wrong answer, which is (150-122) 7=4 questions, so you will answer 26 questions correctly. This is (26*5)-(4*2)=122 points.

Do it right, do x, do it wrong, Y

5x-2y=122

x+y=30

Solve it out x=26

Whatever you ask, you can set one.

Don't forget to lose 2 points if you do a question wrong, so he gets 130 points for 26 questions correctly, and then gets 4 questions wrong and subtracts 8 points, isn't it 122 points?

Let the equation be right.

If you copy x questions, you will get 30-x questions wrong.

5x-2(30-x)=122 can be listed

The resulting number is an infinite decimal and rounded to 25

25 is not in accordance with the original meaning.

25 is not the solution of the original equation.

24 does not correspond to the original meaning.

24 is not the original equation solution.

Not the original equation solution.

The original equation solution does not meet the actual conditions.

The question is a false proposition, and there is no solution to the question.

Unless you can get a few questions right).

Suppose you have done all the questions.

Assuming that everything is done correctly, 30*5=150 points are awarded.

But the actual score is 122 points, the difference is 150-122 = 28 points, then there must be a wrong question, each wrong question is less than 5 + 2 = 7 points, so a total of 28 7 = 4 questions,

There is a difference of 7 points between such a correct question and a wrong question.

So he got 4 questions wrong. Do 26 questions correctly.

30*5=150 (points) du 150-122=28 (points) 28 (5+2)=4 (dao) 30-4=26 (questions) Answer: Xiao Ming Zhi answered a total of 26 dao questions correctly. Assuming that Xiao Ming answers all the questions correctly, then specialize.

He got a total of 150 points, then he got 28 points more, 28 points is the wrong point, yes, not only did he not get 5 points, but also deducted 2 points, so with 28 (5+2)=4 (Dao), he answered four wrong questions, with 30-4=26 (questions) So he answered 26 questions correctly. Please adopt, thank you.

The criteria for judging are: 5 points for each correct question; 2 points will be deducted for each question you get wrong. In this case, you should get 108 points for getting 24 questions right.

25 questions are 115 points for getting 25 questions right, and the answer is 26 questions.

Set Xiao Ming to do the x question correctly.

5x-2(30-x)=122

Solution x=26