sapiental
Feb26-08, 09:54 PM
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!
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!