MathDB
2010 Winter Team #5

Source:

March 19, 2022
number theory

Problem Statement

The popularity of a positive integer nn is the number of positive integer divisors of nn. For example, 11 has popularity 11, and 1212 has popularity 66. For each number nn between 11 and 3030 inclusive, Cathy writes the number nn on kk pieces of paper, where kk is the popularity of nn. Cathy then picks a piece of paper at random. Compute the probability that she will pick an even integer.