Problem:
A fair coin is tossed  times. What is the probability of at least two consecutive heads?
Answer Choices:
A.  
B.  
C.  
D.  
E.  
Solution:
List the possible equally likely outcomes: , , , , , , , . Only , , have at least consecutive heads, so the probability of at least consecutive heads is .
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions