Bitstrings

[smarika]

True or false. The number of 20 character bitstrings that either begin with three "0"s OR end with two "0"s but not both is 2^17+2^18-2^15.
I know it's false but why is it false can someone explain please?

 

[Deleted member 4993]

True or false. The number of 20 character bitstrings that either begin with three "0"s OR end with two "0"s but not both is 2^17+2^18-2^15.
I know it's false but why is it false can someone explain please?

Please show us what you have tried and exactly where you are stuck.

Please follow the rules of posting in this forum, as enunciated at:

READ BEFORE POSTING​

Please share your work/thoughts about this problem.

 

[pka]

True or false. The number of 20 character bitstrings that either begin with three "0"s OR end with two "0"s but not both is 2^17+2^18-2^15.
I know it's false but why is it false can someone explain please?

How do you know that it is false?