There are 80 chickens and rabbits in one feedlot, and a total of 220 feet. So how many chickens and

Assuming that 80 are all chickens, then there are 80*2=160 legs.

A rabbit has 2 more legs than a chicken, so you need to replace (220-160) 2=30 chickens to get 220 legs.

There are 50 chickens and 30 rabbits in the farm.

Substitution method. This is a question for the third grade or so of elementary school, and I used to do this kind of question when I participated in the elementary school math competition in '93.

It is more difficult to do this question in the third grade.

If each critter counts 2 legs, a total of 80 2 = 160 are counted.

There are also 220-160 = 60 feet that are not counted.

These 60 feet are all rabbit's feet, and each rabbit has 4-2=2 legs.

Then there are rabbits 60 2 = 30 and chickens 80-30 = 50.

All animals have at least two legs, and if each animal has 2 feet, 2 * 80 = 160 legs.

The extra number of feet is the number of rabbit feet.

So the number of rabbits is (220-160) 2 = 30.

The number of chickens is 80-30=50

I think we can use the substitution method: if you have all the chickens, you will have 160 legs, and then replace one chicken with a rabbit, you will add 2 feet, and you can replace them. The basic idea of the equation is as follows:

220-160=60，60÷2=30。This 30 is the number of rabbits.

Based on the calculation that each animal has 2 feet, we get 2 * 80 = 160 feet.

The extra number of feet is the number of rabbit feet.

So the number of rabbits is (220-160) 2 = 30.

The number of chickens is 80-30=50

Known: A breeding group raises a total of 78 chickens and rabbits, with a total of 200 feetA rabbit has two more legs than a chicken

Analysis: Suppose that all the chickens in the breeding group are raised, then,78 chickens have a total of 78*2=156 legs。The 78 chickens and rabbits in the question have a total of 200 legs, which is 44 legs more than the 78 chickens.

That is to sayThese 44 legs are more than chickens in rabbits, ieThere are 44 rabbits 2 = 22 pcsThere are 78-22=56 chickens

Formula:(Total number of feet - number of chicken's feet Total number of feet) (Number of rabbit feet - number of chicken's feet) = number of rabbits

Total number of birds - number of rabbits = number of chickens

Calculation: 22 rabbits, a total of 22 * 4 = 88 feet, 56 chickens a total of 56 * 2 = 112 feet, adding up to 88 + 112 = 200, in line with the conditions of the question.

A: The group has a total of 22 rabbits and 56 chickens.

What is a chicken and rabbit cage?

Chickens and rabbits in the same cage is one of the famous typical interesting questions in ancient China, recorded in the "Sun Tzu Sutra".

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The ancient Chinese Sutra of Sun Tzu consists of three volumes, written around the 5th century AD. The book is easy to understand and has many interesting arithmetic problems, such as the "chickens and rabbits in the same cage" problem:

Today there are pheasants and rabbits in the same cage, there are thirty-five heads on the top, and there are ninety-four feet under it.

There are 35 pheasant rabbits in the question, and if the two front feet of the rabbit are tied with a rope and regarded as one leg, and the two hind feet are also tied with a rope and regarded as one leg, then the rabbit becomes a chicken with two legs, that is, the rabbit is first regarded as a chicken with two legs. The total number of feet of chickens and rabbits is 35 2 = 70 (only), which is 94-70 = 24 (only) less than the 94 mentioned in the question.

Untying the rope on a rabbit's feet will increase the total number of feet by 2, that is, 70 + 2 = 72 (only), and then loosening the rope on a rabbit's foot, the total number of legs will increase by 2, 2, 2, 2, 2 ......and continue until it increases by 24, so the number of rabbits: 24 2 = 12 (only), so that the chickens have 35-12 = 23 (only).

Let's summarize the solution idea of this problem: if you assume that they are all chickens, then according to the total number of chickens and rabbits, you can calculate how many feet there are under the assumption, compare the number of feet obtained in this way with the number of feet given in the question, see how much the difference is, every 2 feet indicates that there is 1 rabbit, divide the number of feet by 2, you can calculate how many rabbits there are.

To sum up, the basic relationship for solving the chickens and rabbits in the same cage is: the number of rabbits = (the actual number of feet - the number of chickens and rabbits in each chicken) (the number of feet in each rabbit - the number of feet in each chicken). Similarly, it can be assumed that it is all rabbits.

56 chickens and 22 rabbits.

Solution: If there are x chickens, then there are 78-x rabbits.

2x+（78-x）×4=200

2x+312-4x=200

312-2x=200

2x=312-200

2x=112

x=112÷2

x = 56 rabbits have 78-56 = 22 rabbits.

Set up x chickens. 2x+4*(78-x)=200

2x+312-4x=200

2x=112

x = 56 chickens and 22 rabbits.

If you don't understand, you can ask, it helps, thank you!

The solution idea, assuming that all 78 are chickens, then the feet are 78*2=156, and the actual is 200 feet, so there must be a four-legged rabbit in it, 200-156=44, because the rabbit has two more legs than the chicken, so.

44 2 = 22, 22 rabbits, 78-22 = 56, 56 chickens.

The equation is relatively simple.

Let there be x rabbits, then chickens are (78-x) rabbit feet are 4x, chicken feet are 2 (78-x) The equation is: 4x+2(78-x)=200

4x+156-2x=200

4x-2x=200-156

2x=44x=22

Chickens: 78-22=56.

Do you understand?

Answer: There are 56 chickens and 22 rabbits. The specific calculation process is as follows: there are x chickens and y rabbits. There are x=y=78,x=4y=200 solutions for x=56,y=22

56 chickens and 22 rabbits.

Solution: If there are x chickens, then there are 78-x rabbits.

2x+（78-x）×4=200

2x+312-4x=200

312-2x=200

2x=312-200

2x=112

x=112÷2

x = 56 rabbits have 78-56 = 22 rabbits.

Summary. Assuming that all rabbits are present, then there are a total of feet: 4 78 = 312 (only) more than the actual number of feet:

312-200 = 112 (only) This is because the chickens are treated as rabbits: 4-2 = 2 (only) so the chickens are: 112 2 = 56 (only).

Rabbits have: 78-56=22 (only).

A breeding group has a total of 78 chickens and rabbits, a total of 200 feet, how many chickens and rabbits are raised in the breeding group?

Assuming that all are rabbits, then there are a total of feet: 4 78 = 312 (only) more than the actual number of feet: 312-200 = 112 (only) This is because the chicken is used as a beam to accompany the rabbit Each difference is only counted as a dregs high:

4-2 = 2 (only) so chickens have: 112 2 = 56 (only) rabbits have: 78-56 = 22 (only).

The solution is very simple, the chicken has 2 feet, the rabbit has 4 feet, and the orange block so if 112 are only counted as 2 slow soldiers without feet, then the extra feet are the rabbit's 2 feet.

Number of rabbits = 308 - 112 2 ) 2 = 42.

Number of chickens 112 - 42 = 70.

70 chickens in the feedlot.

Set up a breeding farm Qi Kuanyan chicken x, then rabbit (112-x), because there are a total of 308 feet, chicken two feet, rabbit four legs, so 2x+4(112-x)=308, solve x=70. So there are 70 chickens. Chickens and rabbits in the same cage is one of the famous mathematical problems in ancient China.

About 1,500 years ago, this interesting question was recorded in the "Sun Tzu's Sutra". The essence of this problem is a binary equation. If the teaching method is appropriate, it can help primary school students to understand concepts such as unfortunate numbers and equations, and develop the ability to abstract numbers from application problems.

Generally, in the fourth to sixth grades of primary school, it is taught with the content of one-dimensional equations.

70 chickens in the feedlot.

If there are x chickens in the feedlot, then the rabbit will burn (112-x), because there are a total of 308 feet, two chickens and four rabbits, so 2x+4(112-x) disturbs the slippery town = 308, and the solution is x = 70. So there are 70 chickens.

There are 75 chickens and 25 rabbits.

There are x chickens and y rabbits.

According to the title, there are 100 chickens and rabbits, and the list formula is: x+y=100

According to the title, exactly 250 feet, the columnar formula is: 2x+4y=250

Comprehensively solving this system of binary linear equations, we get:

x=75，y=25

So there are 75 chickens and 25 rabbits.

2x100=200 (only).

250-200=50 (only).

The number of rabbits: 50 divided by 2 = 25 (rabbits).

Number of chickens: 100-25=75 (only).

OK! (*Hee-hee.......)

Solution: Suppose it's all chickens.

100 2 200 250-200 50 4-2 2

50 2 25 (only). Rabbit 100-25 75 (only). Chicken.

Let the rabbit be x

4x+2（100-x）=250

4x+200-2x=250

4x-2x=250-200

2x=50x=25

100-25 = 75 (pcs) chickens.

25 rabbits, 75 chickens.

78x4-200

112 (only).

56 (only) 78-56 = 22 (only).

A: There are 56 chickens and 22 rabbits.

Solution: If there are x chickens, then there are 78-x rabbits.

2x+（78-x）×4=200

2x+312-4x=200

312-2x=200

x = 56 chickens and 56 rabbits have 78-56 = 22 rabbits.