Knuth's Art of Computer Programming, vol 2 [1], not surprisingly, gives a thorough discussion of the balanced ternary system. The solution for a nice brainteas

Knuth's Art of Computer Programming, vol 2 [1], not surprisingly, gives a thorough discussion of the balanced ternary system. The solution for a nice brainteaser can be found quickly once one thinks about balanced trinary, here it is: "Using a balance scale, what is the minimum number of wheights needed to weigh any whole number of grams up to 40g?" [1] http://www.amazon.com/Art-Computer-Programming-Volume-Seminumerical/dp/0201896842 http://www.amazon.com/Art-Computer-Programming-Volume-Seminu...