Okay, but you could also say 19 = 20 - 1 then multiply by 1.6 20 -> 32 1 -> 1.6 and get the estimate 19mi = 30.4km, which is even closer and se

Okay, but you could also say 19 = 20 - 1 then multiply by 1.6 20 -> 32 1 -> 1.6 and get the estimate 19mi = 30.4km, which is even closer and seems rather easier to me than figuring out a set of Fibonacci numbers which sum to 19.