Phebe asked in Science & MathematicsMathematics ยท 1 decade ago

Maths problem - Urgent !?

Qtn : A farmer has chickens and goats in his farm. There are total of 28 animals and 74 legs. How many chickens are there ? Can someone help me ..

16 Answers

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  • 1 decade ago
    Best Answer

    Okay, this is fun. If A is the number of chickens and B is the number of goats, then 2A is the number of chicken legs and 4B is the number of goat legs.

    2A+4B=74 and A+B=28 (solve for A) A=28-B

    Substitue the value of A into the first equation:

    2(28-B)+4B=74

    56-2B+4B=74

    56+2B=74

    2B=18

    B=9

    Pop that into the second equation to get a value for A:

    A+9=28

    A=19

    There are 19 chickens with 2 legs (a total of 38 legs) and 9 goats with 4 legs (a total of 36 legs). This is a total of 28 animals with 74 legs.

  • 1 decade ago

    Straightforward simultaneous equations

    There are 2x chicken legs and 4y goats legs

    Total legs (74) = 2x + 4y

    Total number of animals = x + y = 28

    so x = 28 - y,

    Put that in the first equation gives 56 - 2y + 4y = 74

    So y = 9 and x = 19

    So 9 goats and 19 chickens

  • Anonymous
    1 decade ago

    C is the number of chickens, G is the number of goats.

    74 = 2 x C + 4 x G

    28 = C + G

    Solve the second equation of either C or G (I chose C below) then substitute back into the first equation.

    C = 28 - G

    74 = 2 x (28 - G) + 4 x G

    74 = 56 - 2G + 4G

    18 = 2G.... so there are 9 goats, and that means 19 chickens

  • 1 decade ago

    this can be done in the "false hypothesis method" it goes like this- you assume all of the animals have 4 legs

    it goes 28*4=112

    then you see how many extra feet you have 112-74 = 38

    this is the number of chcken legs - so there are 38/2=19 chickens

    and (74-38)/4 goats ==> 9 goats

    it is a weird method but it workes..

    Source(s): it was taught in the 3 grade or something...
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  • Anonymous
    1 decade ago

    Let c = the number of chickens

    Let g = the number of goats

    You know that each chicken has 2 legs and each goat has 4.

    c + g = 28

    2c + 4g = 74

    Solve for a single variable in the first equation.

    c + g = 28

    c = 28 - g

    Plug that variable into the second equation.

    2(28 - g) + 4g = 74

    56 - 2g + 4g = 74

    56 + 2g = 74

    2g = 18

    g = 9

    That means there are 9 goats.

    c + g = 28

    c + 9 = 28

    c = 19

    That means there are 19 chickens.

  • 1 decade ago

    Let x = number of 4 legged animals and y = number of 2 legged animals

    Then

    x + y = 28

    and

    4x + 2y = 74

    Solve for x and y. Chickens have two legs and goats have 4.

  • kimber
    Lv 4
    3 years ago

    i'm no longer able to answer that, via fact for that fraction, i do no longer know if the numerator is 5, (4+5), (2*4+5). same with the denominator. although, if i anticipate which you recommend: 2 x 4 + (5 / 2) - 3 x 4 + 3 = then stick to the order of operations, PEMDAS. That stands for Parentheses, Exponents, Multiplication, branch, Addition Subtraction. Multiplication and branch are carried out on a similar time yet from left to remarkable, as are addition and subtraction. So first, you could no longer do something with what's in parentheses, and there are no longer any exponents, so initiate with multiplication and branch: (2*4) + (5/2) -(3*4) +3 = 8 + (5/2) -12 +3 Now, upload or subtract from left to remarkable: (8 5/2) -9 convert to incorrect fractions with a denominator of two: 21/2 - 18/2=3/2 So the respond is 3/2.

  • 1 decade ago

    Simultaneous equation.

    Let Chicken be X

    Let Goats be Y

    X + Y = 28 ----------(1)

    2X + 4Y = 74 ---------(2)

    Solve..... X=19 and Y = 9

  • Angela
    Lv 4
    1 decade ago

    Chickens = 19

    And Goat = 9

  • 1 decade ago

    17 goats, and 2 chickens

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