Question

Anne is studying for a history exam covering the French Revolution that will consist of five essay ques- tions selected at random from a list of ten the professor has handed out to the class in advance. Not exactly a Napoleon buff, Anne would like to avoid researching all ten questions but still be reasonably assured of getting a fairly good grade. Specifically, she wants to have at least an 85% chance of getting at least four of the five ques- tions right. Will it be sufficient if she studies eight of the ten questions?

Answer 1

Answer:

Yes it will

Explanation:

The statistic probability that she encounters the two questions not studied among the 5 selected by the professor is 15%. And she has a 85% chance that she either encounters only one question not studied or 5 questions studied by her.