Source: Sent to me by Nikhil Garg (CSE Senior Undergrad, IITD) - who got this from Rudradev Basak Problem: There are K balls in a sack numbered 1 to K. Bob chooses a ball at random notes down its number and puts it back in sack. He does this process for N times. What is the expected value of the frequency of the most frequent element ? Best of Luck! I do not have the solution. So, tell me if you get one. Thanks.