Web Science/Part2: Emerging Web Properties/Simple statistical descriptive Models for the Web/Number of words needed to understand most of Wikipedia/quiz

We saw that more than half of the unique word tokens on Simple English Wikipedia occured only once. Which of the following statements are true?

picking a random word from the simple english wikipedia the chance is higher than 50% that it occured only once
picking 100 random words from wikipedia we expect more than 50 of them to occure only once
picking a random word the chance for getting a word that occurs only once is less than 10%