Q78 / 160 · AP EAMCET 2018 (22 Apr Shift 2) · Mathematics
Two dice are thrown simultaneously. If $A$ is event of getting the sum of the numbers on two dice as greater than or equal to 8 and $B$ is the event of getting a number less than or equal to 3 on atleast one of the die. Then, $P(B / A)=$
- A$\frac{5}{15}$
- Correct answerB$\frac{6}{15}$
- C$\frac{7}{15}$
- D$\frac{8}{15}$
Solution
Event
$$
\begin{aligned}
& \begin{array}{l}
A=(2,6),(3,5),(4,4),(5,3),(6,2),(3,6),(4,5),(5,4) \\
\quad(6,3),(4,6),(5,5),(6,4),(5,6),(6,5),(6,6)
\end{array} \\
& \text { and event } A \cap B=(2,6),(3,5),(5,3),(6,2),(3,6),(6,3) \\
& \text { So, } P(B / A)=\frac{P(B \cap A)}{P(A)}=\frac{n(B \cap A)}{n(A)}=\frac{6}{15} \text { or } \frac{2}{5} .
\end{aligned}
$$
Hence, the correct answer is option: 'B'.