1. The problem statement, all variables and given/known data a) How many bit strings are there of length 8? b) How many bit strings are there of length 8 which begins with 2 1's? 2. Relevant equations Product Rule 3. The attempt at a solution a) Since a bit string is either 0 or 1 there are two possibilities for each one. By the rule of products 2^8 = 256 bit strings. c) the first two choices are fixed so its 11(0/1)(0/1)(0/1)(0/1)(0/1)(0/1) 2^6 = 64 possible different bit strings. when u allow the preceding 1 to change u basically double the 64 combinations and allowing the first one u quadruple it getting back to the original 256. Could someone please confirm my result. Danke!