0 votes 0 votes Number of strings up to length $3$ on alphabet set $\sum$ = { a,b,c,d } are :(including,string of length zero)? $A) 16 $ $B) 85 $ $C) 128 $ $D) 64 $ Combinatory discrete-mathematics combinatory + – Lakshman Bhaiya asked Oct 5, 2018 edited Oct 5, 2018 by Lakshman Bhaiya Lakshman Bhaiya 467 views answer comment Share Follow See all 6 Comments See all 6 6 Comments reply Show 3 previous comments BASANT KUMAR commented Oct 8, 2018 reply Follow Share if i modify the question in such a way that no repitition of same alphabet is allowed then in this case what will be answer??? 0 votes 0 votes Lakshman Bhaiya commented Oct 8, 2018 i edited by Lakshman Bhaiya Oct 8, 2018 reply Follow Share @ BASANT KUMAR If repetition is not allowed _ _ _ (Lenght 3$: 4*3*2 = 24$ ways) _ _ (Length $2: 4*3=12$ ways) _ (Length $1: 4$ ways) (Length $0: 1$ way) So, $24+12+4+1 = 41$ 0 votes 0 votes BASANT KUMAR commented Oct 8, 2018 reply Follow Share yes 41 , i am also getting this. 1 votes 1 votes Please log in or register to add a comment.
Best answer 4 votes 4 votes $\underline{\hspace{0.5cm}} \ \underline{\hspace{0.5cm}} \ \underline{\hspace{0.5cm}} $ 4 options to fill each blank = $4^3 = 64$ $\underline{\hspace{0.5cm}} \ \underline{\hspace{0.5cm}} $ $ =4^2 = 16$ $\underline{\hspace{0.5cm}} = 4^1 = 4$ $1$ $64 + 16 + 4 + 1 = 85$ Mk Utkarsh answered Oct 5, 2018 selected Oct 8, 2018 by Lakshman Bhaiya Mk Utkarsh comment Share Follow See 1 comment See all 1 1 comment reply Lakshman Bhaiya commented Oct 5, 2018 reply Follow Share Wow,it's a easy method. Thanks Brother 0 votes 0 votes Please log in or register to add a comment.