SOLUTION: Mrs. McDonald has a farm with ducks and pigs. There are 27 heads and 84 legs. How many ducks and pigs are on Mrs. McDonald's farm?

Algebra.Com
Question 1031986: Mrs. McDonald has a farm with ducks and pigs. There are 27 heads and 84 legs. How many ducks and pigs are on Mrs. McDonald's farm?
Found 2 solutions by stanbon, ikleyn:
Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
Mrs. McDonald has a farm with ducks and pigs. There are 27 heads and 84 legs. How many ducks and pigs are on Mrs. McDonald's farm?
-----
Legs Eq:: 2d + 4p = 84 legs
Heads Eq: d + p = 27 heads
----------------------------------
Modify for elimination::
d + 2p = 42
d + p = 27
-------------------
Subtract and solve for "p"::
p = 15 (# of pigs)
----
Solve for "d"
d = 27-15 = 12 (# of ducks)
---------------
Cheers,
Stan H.
----------------

Answer by ikleyn(52781)   (Show Source): You can put this solution on YOUR website!
.
See also the lesson Problem on animals at a farm in this site.


RELATED QUESTIONS

A particular farm has cows and ducks. There are a total of 79 heads and 212 legs. How... (answered by edjones)
A farmer has both pigs and chickens on his farm. There are 78 feet and 27 heads. How many (answered by josmiceli,bucky)
A farmer has both pigs and chicken on his farm. There are 78 Feet and 27 Heads. How many (answered by richwmiller)
A farmer has both pigs and chickens on his farm. There are 78 feet and 27 heads. How... (answered by greenestamps,Edwin McCravy)
Mike has only ducks and cows on his farm. The cows and ducks have 52 legs in total.... (answered by Edwin McCravy)
A Farmhouse shelters 10 animals. some are pigs and some are ducks. Altogether there are (answered by japunzalan13)
a farmhouse shelters 10 animals. some are pigs and some are ducks. altogether there are... (answered by Boreal)
in a farm, there are 150 more goats than ducks. there are 1800 animal legs altogether.... (answered by stanbon)
If there are chicken and pigs on a farm, and there are 24 heads and 98 feet, how many... (answered by oscargut)