Chickens and rabbits in the same cage, there are 20 heads, 54 legs, how many chickens and rabbits ar

Head (20) times ten.

Chicken (13) times ten.

Rabbit (07) times ten.

Legs (54) multiplied by ten.

Chicken and rabbit in the same cage concise solution method:

Divide the total number of legs by the number of chicken legs (2) and subtract the total number of heads as the number of rabbits (the number of legs A is one-half of the number of legs of B).

For example, there are 15 $5 bills and $10 bills, with a total amount of $95. How many tickets are 5 yuan and 10 yuan?

Solution: 95 yuan 5 yuan = 19 sheets.

19 - 15 = 4.

A: There are 11 5 yuan tickets and 4 10 yuan tickets.

I do not quite understand! However, I can use the arithmetic method of a math textbook to solve the problem: if these 20 animals are all rabbits, then there should be a total of 20x4 = 80 (strips) more than 54 80-54 = 26 (strips), how is there more than that?

Rabbits have 4 legs, while chickens have only 2 legs. One more than 2, one more 2 26 2 = 13. There are 13 chickens and 20-13 = 3 rabbits.

ps: You can also see them all as chickens, I'm used to seeing them as rabbits! ）

If the rabbit has only two legs, there should be legs in the cage: 20 heads 2 legs = 40.

In fact, a small number of 54-40 = 14 legs.

A small number of legs are because each rabbit has a few legs, so there are rabbits 14 2 = 7 (birds) and chickens have 20-7 = 13 (birds).

Solution: Set rabbits x chickens and chicken y.

Simultaneous equations x+y=20 (1).

4x+2y=54 （2）

by (1) x = 20-y (3).

Bring (3) into (2) 4x(20-y)+2y=5480-4y+2y=54 2y=26 y=13

Substitute y=13 into (1) x=20-13x=7, so x=7

y=13 so there are 7 rabbits and 13 chickens.

Answer the question with the hypothetical method:

20 times 2 = 40 (pieces) 54-20 = 34 (pieces) 34 divided by (4-2) = 17 (pieces) 20-17 = 3 (pieces).

A: There are 17 chickens and 3 rabbits.

Let x be the number of chickens and y be the number of rabbits.

x+y=20

2x+4y=54

The solution is y=7x=13

Assuming that all chickens are present, the number of rabbits = (total number of feet - total number of heads 2) 2;

Number of chickens = total number of heads - number of rabbits.

Assuming that all rabbits are used, the number of chickens = (total number of heads 4 - total number of feet) 2;

Number of rabbits = total number of heads - number of chickens.

There are x rabbits.

4x+2(20-x)=54

4x+40-2x=54

2x=14x=720-7=13

There are 7 rabbits and 13 chickens.

If there is a chicken x there is a rabbit 20-x

2x+4*(20-x)=54

x = 13 with 13 chickens and 20 with x = 7.

Solution: It's all rabbits. Solution: It's all chickens.

26 (4-2) = 13 (13) number of chickens 14 (4-2) = 7 (number) of rabbits.

20-13=7 20-7=13

A: 7 rabbits and 13 chickens.

Solution: Set up x chickens.

2x+4(20-x)=54

The solution is x=13

A: 13 chickens and 7 rabbits.

Let the rabbit be x.

4x ten 2 (20 a x) = 54

4x-2x=54-40

2x = 14x = 7 chickens: 20 - 7 = 13.

Suppose there are x rabbits and y chickens.

x+y=20

4x+2y=54

x=7 y=13 Thank you.

The chicken has 2 legs, the rabbit has 4 legs, assuming that 20 heads are chickens, then there should be 40 legs now 54-40 = 14 more, that is the rabbit has 2 extra legs, that is, the rabbit has 14 2 = 7.

There are 20-7 = 13 chickens.

There are 7 rabbits. The number of legs is halved, and the number of rabbits is obtained by subtracting the number of heads. 54/2 -20=7

There are x chickens.

2x+4(20-x)=54

80-2x=54

2x=26x=13

Then the rabbit has 20-13=7

So there are 13 chickens and 7 rabbits.

Set x chickens and y rabbits:

x+y=20

2x+4y=54

The solution is x=13

y=7A: 13 chickens, 7 rabbits.

Columnar method:

All of them are chickens, and the chickens have 2 legs.

Feet: 2x20 = 40 (strips).

Less than the original, more than the original is the rabbit's foot - the chicken's foot.

Extra feet: 54-40=14

Number of rabbits: 14 (4-2) = 7 (rabbits).

Number of chickens: 20-7=13 (chickens).

Solution: Suppose there are x chickens and 20-x rabbits, 2x+4 (20-x)=54

2x+80-4x=54

80-2x=54

2x=80-54

2x=26x=26÷2

x=13 rabbits: 20-x=20-13=7.

A: There are 13 chickens and 7 rabbits.

There are 12 chickens, 8 rabbits, and two rabbits each have one foot eaten by you.

Chickens and rabbits in the same cage.

There is a formula: rabbits have: (54 20*2) (4-2) 7 pieces.

If there are x chickens, then there are (20-x) rabbits.

2x+4（20-x）=54

80-2x=54

2x=26x=13

Number of chickens: x=13, number of rabbits: (20-x)=7 A: The number of chickens is 13 and the number of rabbits is 7.

13 chickens with 26 legs and 7 rabbits with 28 legs, for a total of 54 legs.