A zoo keeper counted the heads of the animals in a zoo and found it to be 80. When he counted the legs of the animals he found it to be 260. If the zoo had either pigeons or horses, how many horses were there in the zoo? (R.R.B., 2009)
Answer
Answer (as printed):
Explanation
Let the number of pigeons be $x$ and the number of horses be $y$. Then, total number of heads $=x+y$. total number of legs $=2 x+4 y$. $$\therefore \quad x+y=80$$ And, $2 x+4 y=260$ or $x+2 y=130$ Subtracting (i) from (ii), we get: $y=50$. Putting $y=50$ in (i), we get: $x=30$. Hence, number of horses in the zoo $=50$.
Explanation as extracted from the printed page; notation may be imperfect.