Question

Determine the number of bit strings of length 10 that either begin with three 0'S or end with two 1's

Answer 1

Step-by-step explanation:

String of length 10 that begin with 0's

There are two possible bits :0 and 1

First digit =1 way ( has to be 0)

Second digit =1 way( has to be 0)

Third digit =1 way (has to be 0)

Fourth digit =2 ways

Fifth digit =2ways

Sixth digit =2 ways

Seventh digit =2 ways

Eight digit =2ways

ninth digit =2 ways

Tenth digit =2ways

Use the product rule :

1.1.1.2.2.2.2.2.2.2=2^7

=128