or
or
Let the number of buffaloes be x and the number of ducks be y.
Each buffalo has 1 head & 4 legs.
Each duck has 1 head & 2 legs.
So the number of heads =x+y and the number of legs=4x+2y.
So, by the given condition,
4x+2y=2(x+y)+24
⇒4x−2x+2y−2y=24
⇒2x=24
⇒x=12
