Java assignment

In lecture we talked about the trade-off between using linear search on an unsorted list (the phone book) and sorting the list first and then using binary search. We sort the phonebook because we search it enough times that it's worth the computational expense involved in sorting it. Suppose we have an unsorted list of length 250,000. How many worst case searches would be necessary for it to make it worth it to first sort the list with selection sort so that we could then use binary search instead of linear search