algebra
posted by jacob .
a farmer has both cickens and cattle.These animals have a total of 40 heads and 140 feet.How many chicken and how many cattle has this farmer

number of chickens  x
number of cattle  y
x+y = 40
2x + 4y = 140 or x+2y = 70
subtract them
y = 30
then x = 10
The farmer has 10 chickens and 30 cattle
check:
10+30 = 40 heads
20 chicken feet + 120 cattle feet = 140 feet