There are 13 animals in the barn. some are chickens and some are pigs. there are 40 legs in all. How

Discussion in 'Calculator Requests' started by math_celebrity, Oct 30, 2016.

  1. math_celebrity

    math_celebrity Administrator Staff Member

    There are 13 animals in the barn. some are chickens and some are pigs. there are 40 legs in all. How many of each animal are there?

    Chickens have 2 legs, pigs have 4 legs. Let c be the number of chickens and p be the number of pigs. Set up our givens:
    (1) c + p = 13
    (2) 2c + 4p = 40

    Rearrange (1) to solve for c by subtracting p from both sides:
    (3) c = 13 - p

    Substitute (3) into (2)
    2(13 - p) + 4p = 40
    26 - 2p + 4p = 40

    Combine p terms
    2p + 26 = 40

    Subtract 26 from each side:
    2p = 14

    Divide each side by 2
    p = 7

    Substitute p = 7 into (3)
    c = 13 - 7
    c = 6

    For a shortcut, you could use our simultaneous equations calculator
     

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