Farmer Joe has pigeons and sheep on his farm.
He has a total of 16 animals and can count 40 legs.
How many pigeons and how many sheep does he have?
SOLUTION
Let the pigeon be x and the sheep be y
x + y = 16 --------------------- equ 1 x 2 = 2x + 2 y = 32 ---------- equ 3
2 x + 4 y = 40 ---------------- equ 2
equ 2 minus equ 3 , we have :
2x - 2x + 4 y - 2y = 40 - 32
2 y = 8
Divide both sides by 2
y = 8 / 2
y = 4
put y = 4 in equ 1 ,
x + y = 16 .............. equ 1
x + 4 = 16
x = 16 - 4
x = 12
CONCLUSION : There are 12 pigeons and 4 sheep.