+19 Three fair quarters are tossed, and a tail appears on at least one of them. What is the probability that at least one head appears? Express your answer as a common fraction.
+1918 First, let's find the total number of cases we work through. We can actually just list them all out.
We have
\((HHT,HTH,HTT, THH, THT, TTH, TTT)\)
The only possibility where a head doesn't appear is TTT. That means that
\((HHT,HTH,HTT, THH, THT, TTH)\) all work.
Since probability is essentially \(\text{Probability} = \frac{\text{# of Favorable Outcomes}}{\text{Total Outcomes}}\)
So we just have \(\frac{6}{7}\)
So 6/7 is our answer.
Thanks! :)
