Answer:
[tex]2^{100} * 6[/tex]
Step-by-step explanation:
length of finite strings = 100
number of letters : 4 { a,b,c,d }
Determine the number of strings that use ≤ two different letters
since the number of letters is 4 and we are allowed to make use of at most 2 different letters
Then the number of ways will be : [tex]^{4} C_{2}[/tex] = 6 ways
now considering the length of the Finite strings
The number of strings that use no more than two different letters
= [tex]2^{100} * 6 ways[/tex]
