In a group of buffaloes and ducks the number of legs are 24 more than twice the number of heads. What is the number of buffaloes in the group ?

Let the number of buffaloes be x

 and number of ducks be y.

Now, number of heads = x+y

Number of legs = 4x+2y  .......(1) 

But given that legs = 2(x+y)+24 ......(2)

solving (1) & (2),we get

4x+2y=2x+2y+24 

--> x=12.

Therefore number of buffaloes =12