Answer
$P(at~least~one~tail)=\frac{31}{32}$
Work Step by Step
Let's find the probability of getting no tail:
$P(no~tail~five~times)=P(not~a~tail)^5=(\frac{1}{2})^5=\frac{1}{32}$
The event "getting at least one tail" is the complement of the event "getting no tail":
$P(at~least~one~tail)=1-P(no~tail~five~times)=1-\frac{1}{32}=\frac{31}{32}$
