Math Problem is it correct?? plz help its only a 8th grade math problem!?

Question

Ok...theres a farmer. when u ask hom how many chickens and rabbits there are he wont tell u. he just says there are 18 heads and 58 animal feet. how many chickens and how many rabbits are in the yard.

my answer: 8 rabbits and 11 chickens
is that right??
it came out to 58.
plz help and if i did it wrong explain how i should do it plz!!
thank you!!

Answer 1

OK - so we know that chickens have 1 head and 2 feet and rabbits have 1 head and 4 feet.

So let x = chickens and y= rabbits

x + y = 18 (heads)
2x + 4y = 58 (feet)


Two equations, two unknowns. Let's use addition and subtraction method of linear equations. Double first equation

2x + 2y = 36
2x + 4y=58

Subtraction second from first

-2y = -22
y =11.

Substitute
x + 11 = 18
x=7.

So there are 7 chickens, and 11 rabbits.

Let's check

7 + 11 = 18 TRUE

2 (7) + 4(11) = 58??
14 +44 =58??
58 =58 YES!!


Hope that helps!

Answer 2

Please note: 8 rabbits and 11chickens have 19 heads total!

Let R be the # of rabbits
C the # of chickens

(a) C + R = 18, counting the heads.

counting feet:

(b) 2*C + 4*R = 58, two equations in two unknowns.

Since (a) C = 18-R, substitute in (b), which becomes

(b) 2*(18-R) + 4R = 58 or
36 - 2R + 4R = 58 or

2R = 58-36 or
2 R = 22, so
R = 11.

There are 11 Rabbits, and 7 chickens; total of 18 heads.

Check the feet:
4*11 + 2*7 = 44 + 14 = 58. Done.

Answer 3

> my answer: 8 rabbits and 11 chickens

That can't be right. That means:
Number of heads = 8+11 = 19 (wrong!)
Number of feet = 32 rabbit feet + 22 chicken feet = 54 feet (wrong!)

There are a couple of ways to solve this, depending on whether you know algebra or not.

If you know algebra:
---------------------------
Make a variable "R" that stands for "number of rabbits" and "C" that stands for "number of chickens."

Now, the number of heads must be: R+C, so:
heads = R+C = 18

For the feet: the number of rabbit feet is 4 x R (also written as 4R); and the number of chicken feet is 2 x C (also written as 2C). So:
feet = 4R + 2C = 58

From that point, you can use algebra to figure out how much R is and how much C is.

If you DON'T know algebra:
--------------------------------------
Then you need to use trial and error. Here's how I would do it:

Try 9 rabbits and 9 chickens (that automatically gives you the right number of heads), then figure out how many feet that is.

If it's too many feet, cut down on the many-footed creatures (the rabbits); and try 8 rabbits and 10 chickens.

Or, if it's not enough feet, add more rabbits, so 10 rabbits and 8 chickens.

Keep trying that (adjusting the rabbits & chickens one at a time, always keeping a total of 18 animals) until you get 58 feet.

Answer 4

No, thats not correct, 11 chickens and 8 rabbits add up to 19 heads, and 54 feet. to figure it out you would use the algebra equation below and let x=chickens and y=rabbits

feet = 2x+4y=58
head= x+y=18

Next standarze and eliminate:

2x+4y=58
2x+2y=36
2x cancels out and:
2y=22
y=11
11 rabbits

Next substitute 11 for y

2x+44=58
x+11=18
2x=14
x=7

You get 7 chickens and 11 rabbits

Answer 5

the answer is 4 neglected questions out of 20 questions complete a million) 80% = 16 questions 2) 40% = 8 questions provided that 1/2 of 80 is 40 and 1/2 of 16 is 8 3) 20% = 4 questions provided that 1/2 of 40 is 20 and 1/2 of 8 is 4. 80%+20%= one hundred% so provided that 80% equals 16 questions you would possibly want to characteristic 20% it is 4. you presently understand there are 20 questions so if he were given 16 top 20-16= 4 4 neglected inquiries to analyze: provided that there are 20 questions each question is quite worth 5 factors (one hundred/20= 5) 16*5 = 80 ----yeah i noe im a math geek----

Answer 6

Write some equations.

let C = # of chickens
let R = # of rabbits

Heads:
C + R =18
Feet
2C + 4R = 58
7 chickens
11 rabbits

If you write equations for problems like this you will always get them right.