1 votes 1 votes A man with n keys wants to open a lock. He tries his keys at random. The expected number of attempts for his success is (keys are replaced after every attempt) a) n/2 b) n c) √ n d) None of the above Probability isro-ece engineering-mathematics expectation + – sh!va asked Mar 1, 2017 retagged Mar 9, 2019 by Naveen Kumar 3 sh!va 2.2k views answer comment Share Follow See all 21 Comments See all 21 21 Comments reply Show 18 previous comments sushmita commented Mar 3, 2017 reply Follow Share here we are asked number of trials and whenever no of trails are asked it is geometric distribution. 0 votes 0 votes Rahul Jain25 commented Mar 3, 2017 reply Follow Share Thanks @sushmita. https://en.wikipedia.org/wiki/Geometric_distribution?wprov=sfla1 0 votes 0 votes Akriti sood commented Mar 3, 2017 reply Follow Share @sushmita,is it true in every case?? 0 votes 0 votes Please log in or register to add a comment.