7 P. 127

retour

1. \[\begin{aligned} P(\mathrm A)\times P_{\mathrm A}(\mathrm B) &= \frac 1 2 \times \frac 1 3 = \frac 1 6.& \\ P(\overline{\mathrm A})\times P_{\overline{\mathrm A}}(\mathrm B) &= \frac 1 2 \times \frac 1 3 = \frac 1 6.& \end{aligned}\]

2. \[P(\mathrm B) = \frac 1 6 + \frac 1 6 = \frac 2 6 = \frac 1 3.\]

retour

code : 127007