\begin{questions}
\item \emph{Vrai}. $P(\overline{C})=1-P(C)=1-0,3=0,7$.

\item \emph{Faux}. $P(C\cap T)=P(C) \times p_C(T)=0,3 \times 0,2=0,6$.

\item \emph{Vrai}. $P_C(\overline{T})=1-P_C(T)=1-0,2=0,8$.

\item \emph{Faux}. $P(\overline{C}\cap T)=P(\overline{C} \times p_(\overline{C}(T)=0,7 \times 0,1=0,07$.

\item
\begin{questions}
\item \emph{Faux}. $p_C(T)=0,2 \neq 0,13$.
\item \emph{Vrai}. $P_T(C)=\dfrac{P(C\cap T)}{P(T)}=\dfrac{0,06}{0,13}\approx 0,462$.
\end{questions}

\end{questions}
