Question

5. A farm has cows and ducks. Between them, these animals have 78 feet

and 27 heads. How many of each animal are there? Show how you know.​

Answer 1

1 cow has 4 legs and 1 duck has 2 legs

c= the # of cows
d= the # of ducks

78 feet —> 4c+2d =78
27 feet —> c+d=27

4c+2d=78/:2
c+d=27/•(-1)