Question 632950

Let

Chickens = x 
Cows = y

Thirty Heads
x+y=30
x=30-y...................(1)
Hundred Feet
2x+4y=100 
2(x+2y)=100
2(x+2y)/2=100/2
x+2y=50...................(2)
Substitute the value of x from (1) to (2)
30-y+2y=50
30+y=50
y=50-30
y=20
put the value of y in (1)
x=30-y
x=30-20
x=10


Chickens = x = 10 
Cows = y = 20