This study is being conducted to learn more about the safety and effect of telaprevir in combination with peginterferon alfa-2a (PEG-IFN) and ribavirin (RBV) in participants with hepatitis C who have never been treated for their hepatitis C virus (HCV). The study is designed to look at the relative benefits of 24 or 48 weeks of total treatment in people who respond quickly to a telaprevir-based treatment.