About the math problem of staying in a hotel, a math problem has three people going to stay in a hot

It's not like a math problem, uh... It's a bit like a brain teaser for a pit man. Maybe that's the charm of this kind of topic.,It's crazy.。。

In fact, it seems to me that it is the expression of words that has caused us to fall into the quagmire.

Original: This notation is incorrect, it leads us into a misunderstanding.

Yes, the three of them only spent 9 yuan each, which is 27 yuan, but when they calculated the general ledger, they didn't add the 2 yuan, so why not add the 2 yuan - because the 2 yuan was already included in the 27 yuan!!

Therefore, the 27 yuan plus 3 yuan is actually returned to the three of them, which is 30 yuan.

Think about it, don't you?

This is a language trap solution 1: a total of 30, the boss 25 + customer 3 yuan + waiter 2 yuan = 30 solution 2: the customer pays a total of 27 yuan = the boss's 25 yuan + the waiter's 2 yuan solution 3:

The room fee is 25 yuan, that is, 1 yuan per person = the sum of the fees for three people is 28 + 2 yuan for the waiter = 30 handmade. Hope o( o

Actually, the reason is very simple.

27+2, it doesn't mean anything, these two numbers can't be added together at all. The reason is very simple, what is 27, is the sum of 25 yuan of the actual room fee and the 2 yuan hidden by the waiter. It already contains 2, and adding 2 doesn't make sense.

Correct calculation: the actual room fee is 25 yuan, and the waiter hides 2 yuan, which is a total of 27 yuan; "The remaining 3 yuan was distributed to the three people, and each person was given 1 yuan", 27 + 3 = 30, which is the money paid by the first three people. In this way, there is no contradiction.

27+2 is 29, but it should be 27-2=25, their actual cost is 25 plus 2 yuan for the waiter, and the 3 yuan for the additional refund is a total of 30 yuan, that's right. 27 yuan is the accommodation fee, 25 yuan and the waiter's 2 yuan, plus 2 yuan, which is equivalent to turning the three yuan refunded into 2 yuan, which is one yuan less.

27+2 can't be counted like this, my classmates have also done it for me, and I am also confused by 27+2=29 and not =30, but please get out of the trap of 27+2 to confuse you. It actually cost 25 yuan, and the waiter received 30, hid 2 yuan and returned 3 yuan, which was equal to 30 yuan!

Thinking about it backwards, the three of them paid a total of 25 yuan, plus the two yuan taken by the waiter, it is 27 yuan, plus the three yuan returned, it is 30. It's a trap, you can't count it with 10-1 9, are they paying 9 bucks each? No, they each paid 25 3 yuan, plus the money returned, that is, it adds up to 2 is thirty, don't be confused by the equation given in the title, he is wrong.

I think it should be calculated like this: "The 20 taken by the maid is also included in the 90 spent by the priest, so they spent 3*90=270, plus the returned 10 yuan, which is exactly 300".

Same story, take a look.

The three of them went to stay overnight, and the waiter said that they wanted 30 yuan, and each person gave 10 yuan each, making up 30 yuan. Later, the boss said that today's **, only 25 yuan, so he asked the waiter to take the 5 yuan returned to them. The waiter wanted to hide the 2 yuan himself, so he returned the remaining 3 yuan to them.

The three people each got $1 back. 10-1=9 means that only 9 yuan is out for accommodation. 9*3 + 2 yuan for the waiter = 29, what about the remaining 1 yuan?

That's not how the accounts are calculated.

Thirty dollars is still thirty dollars.

Thirty yuan: They gave the boss a total of 25 yuan, plus 1 yuan (3 yuan) per person, a total of 28 yuan, plus the waiter kept 2 yuan, a whole 30 yuan.

Thirty yuan: They spend nine yuan each, which is twenty-seven yuan, which already includes the two yuan kept by the waiter, and can not be added, and each of them has one yuan left in their hands, plus these three yuan or thirty yuan.

The misleading problem of this problem lies in the fact that the money that has already been spent (27 yuan) is added to the duplicate accumulation: the two yuan that the waiter keeps privately (in fact, these two yuan are included in the 27 yuan) without adding the money that should be added (the three yuan recovered), so it will be one yuan less. /

This yuan is only an error caused by subtracting the two yuan that should be added from the three yuan that should be added, so it is one yuan less.

What if the waiter leaves three yuan and five corners? Everyone is only looking for five corners, you still count like this, see what happens?

Then it became: plus the yuan left by the waiter, it became 32 yuan.

Haha, not only is it not less, but there are more binary things!

Do you understand?

This is a one-element quadratic equation problem:

Let the house price be set at X yuan and the profit will be y

y=[50-(x-180)/10]*(x-20)

Solution: Set up 2, 3, and 4 person rooms to rent x, y, and z rooms.

x+y+z=7 ┅┅1)

2x+3y+4z=20 ┅┅2)

2)-(1)*2 obtains: y+2z=6 z=3-y 2Because x,y,z are positive integers, y=2 or y=4

When y=2, z=2, x=3

When y=4, z=1, x=2

The calculation shows that both of them are in line with the topic.

3 for 2 people, 2 for 3 people, 2 for 4 people

Let abc, a+b+c=7

2a+3b+4c=20

a>=1

b>=1

c>=1

Among them, the b in the 3 people must be even. Because the total number of people is an even number, and 3 is an odd number.

If each type of room is rented in x, y, and z rooms, then x+y+z=7 2x+3y+4z=20 x,y,z are all positive integers, so x=3,y=2,z=2This kind of problem is to list the equation relationship of the relevant equation according to the known, and consider whether there are any constraints, and combine these to solve the equation.

Hope it helps.

There are 2 people in the room, 3 people in the room, and 4 people in the room.

Then there is 2x+3y+4z=20 (total number of people).

x+y+z=7 (total number of rooms).

However, the equations listed in this problem according to the known conditions are not enough to solve, and there is more than one solution in the first place.

The equations are based on known conditions, and these two equations are based on the total number of people and the total number of rooms.

There are 2 people in the room, 3 people in the room, and 4 people in the room.

Then there is 2x+3y+4z=20 (total number of people).

x+y+z=7 (total number of rooms).

However, the equations listed in this problem according to the known conditions are not enough to solve, and there is more than one solution to this problem.

The equation is based on known conditions, and these two equations are based on the total number of people and the total number of rooms.

Solution: Set up 2, 3, and 4 person rooms to rent x, y, and z rooms.

x+y+z=7

2x+3y+4z=20

2)-(1)*2 gets: y+2z=6

z=3-y/2

Because x, y, z are.

Zhengyuanfeng rectified which number.

Therefore y=2 or y=4

When y=2, z=2, x=3

When y=4, z=1, x=2

The calculation shows that both of them are in line with the nuclear crack code of the topic.

Solution: There are x cars.

Cargo weight = cargo weight, so it is possible to not empty the inequality according to the last car dissatisfaction. Burying.

If the last reed truck is full, the goods are overcounted; If the last one is empty, the cargo is noisy or undercounted.

That is, more than the last car without 8 (x-1) and less than the last car with 8x.

So you can column: 8(x-1)<4x+20<8x5 because x is an integer, so x=6