Quote:
First, consider the eight base soft drinks on the menu (including cola, root beer and slush mix). If you make no assumption about how many add-ins are used, then there are two possibilities for each of the 16 add-ins: Either you use it or you don’t. Multiply the two possibilities 16 times, and you get 65,536 possible combinations of add-ins for each base drink. Multiply that by eight, subtract one — because no one orders flavorless slush mix by itself — and you get 524,287. Then there are five more base drinks that are made up of one of the add-ins, plus water (such as Powerade). Each of these have one fewer add-in possibility, as you wouldn’t add Powerade to Powerade. Multiply 5 by 2^15 and you get 163,840. Add them up, plus six other beverages that don’t come with add-ins (such as coffee and orange juice) and you arrive at 688,133.