I have been enjoying reading Keith Devlin’s new book, Finding Fibonacci. I’ll write more about the book later. For now, I just wanted to share a nice problem I learned about which Leonardo Pisano, aka Fibonacci, included in his book Liber abbaci. First published in 1202, this is the book that introduced the Hindu-Arabic number system to the Western world. Apparently this problem is well-known among mathematicians, but I had never heard it. Here it is, as translated from Latin by Laurence Sigler:
A certain man buys 30 birds which are partridges, pidgeons, and sparrows, for 30 denari. A partridge he buys for 3 denari, a pigeon for 2 denari, and 2 sparrows for 1 denaro, namely 1 sparrow for 1/2 denaro. It is sought how many birds he buys of each kind.
Can you solve it?