0 0 votes closed as a duplicate of: GATE CSE 2015 | Set 3 | Question: 5 How many 4 digit No's having their digits in non decreasing order (left to right ) constructed by using the digits 1,2,3 only ? Combinatory discrete-mathematics + – Ashish Roy 1 625 views comment Share Follow Print See all 3 Comments 3 3 Comments reply Utkarsh Joshi commented Oct 29, 2018 reply Follow flag Is it 15?Ashish Roy 1 0 0 replyShare akash.dinkar12 commented Oct 29, 2018 reply Follow flag https://gateoverflow.in/8399/gate2015-3-5 2 2 replyShare Utkarsh Joshi commented Oct 29, 2018 reply Follow flag considered 4 digits number using 1,2,3,4 hence got 35. For 3 digits number it would be 15 only. 0 0 replyShare Please log in or register to add a comment.