Problem:
A radio program has a quiz consisting of multiple-choice questions, each with choices. A contestant wins if he or she gets or more of the questions right. The contestant answers randomly to each question. What is the probability of winning?
Answer Choices:
A.
B.
C.
D.
E.
Solution:
The probability of getting all questions right is . Because there are ways to get of the questions right and wrong, the probability of getting exactly right is . Therefore the probability of winning is .
The problems on this page are the property of the MAA's American Mathematics Competitions