Posted by bill on .
farmer fred had chickens and cows on his farm. he knows that together there are 108 legs and 30 heads. how many of each type of animal does he have?

math 
Steve,
c chickens have 2c legs
m cows have 4m legs
c+m = 30
2c + 4m = 108
multiply the top equation by two, and subtract
2c + 2m = 60
2c + 4m = 108
2m = 48
m = 24
c = 6