0 votes 0 votes The number of ways in which 6 rings can be worn on the four fingers of one hand is: a. 360 b. 4^6 c. 6C4 d. 6^4 Desert_Warrior asked Feb 17, 2016 Desert_Warrior 1.1k views answer comment Share Follow See all 4 Comments See all 4 4 Comments reply Jhunjhunuwala commented Apr 12, 2016 reply Follow Share Let x1 be the no. of rings on first finger, x2 on second,x3 on third and x4 on fourth, then x1 + x2 + x3 + x4 = 6 using C(n+r-1,r) the solution is 9C6 = 84 what is wrong in this approach? 1 votes 1 votes srestha commented Apr 12, 2016 reply Follow Share I think it is more accurate 0 votes 0 votes Jhunjhunuwala commented Apr 12, 2016 reply Follow Share But the answer does not match to any of the options.. Moreover I could not find the difference between the two approches 0 votes 0 votes sid1221 commented Jun 6, 2017 reply Follow Share if you use this method , ring should be identical .. which is not mentioned 1 votes 1 votes Please log in or register to add a comment.
Best answer 2 votes 2 votes Ans B) option, you can put one ring in any of 4 fingers so it becomes 4*4*4*4*4*4. UK answered Feb 17, 2016 selected Apr 12, 2016 by Desert_Warrior UK comment Share Follow See all 2 Comments See all 2 2 Comments reply Desert_Warrior commented Feb 18, 2016 reply Follow Share Thanks. But my approach about this question is : we have to select 4 rings out of 6 rings. and then we have 4! arrangements. so the result is : 6C4 * 4! = 360 Could you please tell me where i'm going wrong? 0 votes 0 votes UK commented Feb 18, 2016 reply Follow Share What you are doing is permutation without repetition means only one ring on one finger, but there is no such constraint in the ques. So 4^6 is the ans which is permutation with repetition allowed. 1 votes 1 votes Please log in or register to add a comment.
0 votes 0 votes Case(1) When all rings are same x1+x2+x3+x4=6 C(n+r-1,r) =9C6 =84 Case(2) All are distinct n u require all rings to worn then C(n+r-1,r)*n! =9C6*6! =60480 ManojK answered Apr 12, 2016 ManojK comment Share Follow See all 0 reply Please log in or register to add a comment.