0 votes 0 votes number of integers in the set {0,1,2,3......,10000}which contain digit 5 exactly once ???? i got the 9*9*9*9 is it right??? Combinatory discrete-mathematics + – vijju532 asked Jun 19, 2018 vijju532 335 views answer comment Share Follow See all 3 Comments See all 3 3 Comments reply Tesla! commented Jun 19, 2018 reply Follow Share single digit number - 1 double digit number - 17 (9+8) (15,25,35,45,65,75,85,95,50,51,52,53,54,56,57,58,59) triple digit number - 225 (9*9 + 8*9*2)(5XX, X5X, XX5) quadruple digit number - 2673 (9*9*9 +8*9*9*3) (5XXX.X5XX,XX5X,XXX5) total 2916 or 9*9*9*4 1 votes 1 votes Shubhgupta commented Jun 19, 2018 reply Follow Share fix 5 in every position, (consider every number is 4 digit number then) 5XXX +X5XX +XX5X +XXX5 (9*9*9*1 + 9*1*9*9 + 9*9*1*9 + 9*9*9*1) =4*9*9*9 0 votes 0 votes kavya kamish upadhya commented Jul 6, 2018 reply Follow Share Thanks for the Answer 0 votes 0 votes Please log in or register to add a comment.