1 Chicken have = 2 legs
1 Cow have = 4 legs
No of cows = x
No of chickens = y
Total no of legs = 4x + 2y = 210.............(1)
Total No of heads = x + y = 84................(2)
x = 84 - y....( from (2) )
Substituting the above equation in (1)
4 ( 84 - y) + 2y = 210
336 - 4y + 2y = 210
336 - 2y = 210
-2y = -126
= y = 63
No of cows = 84-63 = 21
∴ Total no of cows = 21
Total no of chickens = 63
