My classmates math problems?? Can you help me look at the math problem?

It's a kind of trick-like subject, if you follow his train of thought, you will only be puzzled, but a little bit of thinking will reveal the mystery. First of all, the 90 yuan spent per person has included the 20 yuan hidden by the waiter (i.e., ***250 yuan + 20 yuan hidden by the waiter = 270 yuan = 3 * 90 yuan) Therefore, the 20 yuan hidden by the waiter cannot be counted when calculating the composition of the 300 yuan, but the 10 yuan returned to each person should be added. Namely:

3 * 90 + 3 * 10 = 300 yuan is just right!

300 yuan will be refunded, 50 yuan and 250 yuan. 250 3 = Now the waiter deducts 20 yuan and gets 10 yuan each, and everyone spends it. There is no bad money.

There's a problem with concept swapping. It's pretty much the same as a mathematical proof of 4=3. We assume that a+b=1 is 4+3=7

Wait for the concept to be swapped to get 4=3...

Each person paid 100 yuan. Refund of 10 yuan = 90 yuan. But they didn't calculate, but they should be 250 yuan, 3+10=yuan.

Each person actually paid 90 yuan (100 yuan per person first, and then 10 yuan per person was refunded), so the three people actually paid a total of 270 yuan. There's nothing wrong with that. The key problem is that the 20 yuan that the waiter hid is already included in the 270 yuan.

In other words, of the 270 yuan, 250 yuan paid for the accommodation fee, and 20 yuan was hidden by the waiter. Therefore, 270 yuan plus 20 yuan is a meaningless calculation, which is unreasonable, purely misleading, and causes confusion in thinking. So, if you want to talk about the relationship between 270 yuan and 20 yuan, it is the relationship between 20 yuan and 270 yuan.

It can be said that 270 yuan minus 20 yuan, that is the accommodation money, 270 yuan (actually paid by three people) plus 30 yuan (returned by three people), this is the original 300 yuan. What's the problem with the $10 missing? This topic is a confusion of thinking, resulting in strange results.

Boss that. If you think of it this way, it's simple: 250+30+20=300

Now I'll switch positions: 10 + (240 + 30) + 20 = 300

Now I understand where the 10 yuan is, the three of them are still 90 each, and the waiter still takes 20, but the boss still has 10 yuan

The crux of the problem is not right.

It only takes one question to illustrate and it will be understood.

$20 is within $270.

That is, the guest only took out a total of 270 yuan, the boss charged 250 yuan, 20 is not outside 270, can not go +20, and the 30 returned is only outside 270.

This question should be thought of like this, the three people each took out 90, a total of 270 yuan, of which 250 yuan was taken by the hotel owner, and the other 20 yuan was taken by the waiter. So 250 + 20 = 270 is right.

Besides, the boss has 250 yuan, and the three people each have 10 yuan, which is 30 yuan, plus 20 yuan in the hands of the waiter, that is, 250 + 30 + 20 A total of 300 yuan, no less.

What about the boss, the actual return is 30, the guy accounts for 20, and there is 10 yuan in the boss, if the guy accounts for 30, then the boss should withdraw to 60, not 50

I think you have a bad head, let me ask you where the 300 yuan came from? Now the amount of money spent by the three of them is 270 yuan, what does it have to do with the 300 yuan? And why use $270 plus $20?

What is the reason for adding it up? Why don't you use $250 minus $300 equals -$50 and say you've earned $50 yourself? And why use $300 to subtract $290?

Why don't you use 500 yuan minus 290 yuan and say that 210 yuan ** went? Is this purely a non-schooled calculation method? There is no reason for this!

Summary. 200x+50y=5500

150x+80y=7100

Can you help me look at the math problem?

Hello, you can.

Tell me. 22 questions.

First, let's set up a system of equations.

200x+50y=5500150x+80y=7100 Find x and y.

You can just send the answer as a whole<>

Hold on. A badge is 10 yuan, and a doll is 70 yuan.

What's wrong. There is a specific process.

Good. You can only have one question at a time, and you have to buy it again for the second question.

Yes. Doesn't he belong to all of the 22 questions<>?

Oh, that's a question.

Ask about custom messages].

A person bought a chicken for 9 yuan, sold it for 10 yuan, and then he thought it was not cost-effective, bought it back for 11 yuan, sold it to another person for 12 yuan, and asked him how much money he made?

Answer] Let's say I have $10 (or $x) on me. I bought a chicken for 9 yuan. Then I have 1 (x-9) yuan left.

Then I sold it for 10 yuan! Then I have 11 (x+1) yuan on me! But it's not over yet, I don't think the deal is worth it, and I have to buy the chicken back for 11 yuan when the flower withers down!

Ha ha! Then I don't have any money (x-10), but fortunately, I found a good man, and he paid 12 yuan for my chicken, so I ended up with 12 (x+2) yuan. So compared to the 10 (x) yuan I had before my brother's rebellion, I earned 2 yuan!

Note that the parentheses indicate that you have x dollars on you. 10 yuan is a specific example to illustrate, so it can't be wrong!

If you're playing brain teasers.

That's the way to go! He was supposed to earn 3 yuan, but he only earned 2 yuan. So I lost a dollar!

1 Because 10 m in 20,10 n liter mu 1 5, so 10 (m-n) 10 m 10 n 100 sells with 10 2, so m-n 2, then 8 m 2 (3n).

8^(m-n)

The first empty (rectangle area = length * width = 14 * 5 = 60 rectangle perimeter = (length + width) * 2 = (14 + 5) * 2 = 38) the second empty is the known area and width to find the length 54 6 = 9

Circumference = (6 + 9) * 2 = 30

There are x people, y questions.

y=5x+3

y=4*2+6(x-2)

The solution is x=7y=38

There are a total of 38 food for thought.

Solution: There are x students.

2*4+（x-2）*6=5x+3

8+6x-12=5x+3

6x-4=5x+3

6x-5x=4+3

x=77*5+3=38 channels.

A: There are a total of 38 reflection questions.

Solution: Let x be the number of students.

5x+3=8+(x-2)×6

x=7 There are a total of 7 5+3=38 reflection questions.

Solution: There are x students.

2*4+（x-2）*6=5x+3

8+6x-12=5x+3

6x-4=5x+3

6x-5x=4+3

x=77*5+3=38 channels.

A: There are a total of 38 reflection questions.

There are x people, y questions.

y=5x+3

y=4*2+6(x-2)

The solution is x=7y=38

There are a total of 38 food for thought.

Solution: There are a total of x students.

5x+3=2*4+6(x-2)

5x+3=8+6x-12

x=-7x=7, then there are a total of 7*5+3=38 reflection questions.

Profit and loss issues.

2 people do 4 courses each, and the rest of the people do 6 courses each, just done."

Explain that if each person is required to do 6 questions, there will be two people who are missing 2 questions each, so the total difference is 3 (6-4) 2=7 questions, and the difference in the number of questions each person does is 6-5=1.

Number of people 7 1-7 Number of questions 7 5 3=38.