0 votes 0 votes q.1) find number of 5 digit number in which digit are in ascending order. BASANT KUMAR asked Oct 11, 2018 BASANT KUMAR 643 views answer comment Share Follow See all 7 Comments See all 7 7 Comments reply Subarna Das commented Oct 11, 2018 i edited by Subarna Das Oct 11, 2018 reply Follow Share for ascending, we need to avoid $0$, we cannot place it anywhere, so we're left with $9$ options, So, we'll be choosing $5$ digits out of $9$,i.e. $^9C_5$ and after choosing there is only $1$ way to arrange them. ∴ Answer will be $^9C_5 \times 1 = ^{9}C_5 = 126$ 4 votes 4 votes Shaik Masthan commented Oct 11, 2018 reply Follow Share what about repetition of digits? 0 votes 0 votes srestha commented Oct 11, 2018 reply Follow Share repetition not allowed 0 votes 0 votes BASANT KUMAR commented Oct 11, 2018 reply Follow Share in question it is mention that we have to arrange in ascending order ,have you any such number in which digit is repeated but it's still in ascending order??? 0 votes 0 votes Shaik Masthan commented Oct 12, 2018 reply Follow Share @BASANT then it is non-decreasing order... @srestha mam i didn't ask for this particular question, i asked for generally, due to it's look more tough.. May anyone have any simple method? 1 votes 1 votes srestha commented Oct 12, 2018 reply Follow Share @Shaik in that case ans also be same because , take any example like 2235 arrangement done in 1 way only 0 votes 0 votes Shaik Masthan commented Oct 12, 2018 reply Follow Share no mam, check this question https://gateoverflow.in/8399/gate2015-3-5 and should check the first link provided on the comment on the question 0 votes 0 votes Please log in or register to add a comment.
1 votes 1 votes out of 1,2,3,4,5,6,7,8,9 pick any 5 digits. only one way to arrange them(ascending order). So, 9C5. Utkarsh Joshi answered Oct 11, 2018 Utkarsh Joshi comment Share Follow See all 0 reply Please log in or register to add a comment.