Search any question & find its solution
Question:
Answered & Verified by Expert
$A$ and $B$ are the two groups of books. Group $A$ consists of 8 science and 5 engineering books and the group $B$ consists of 6 science and 7 engineering books. When an unbiased die is rolled, if 2 or 5 turns up, a book is selected at random from the group $A$. Otherwise a book is selected at random from the $B$ group. When an unbiased die is rolled, the probability of selecting a science book is
Options:
Solution:
2508 Upvotes
Verified Answer
The correct answer is:
$\frac{20}{39}$
Let $E=$ Science book selected
If 2 or 5 turns up after thrown a dice, then select a subject from $A$ otherwise from $B$.
$$
\therefore P(E)=\frac{2}{6} \times \frac{8}{13}+\frac{4}{6} \times \frac{6}{13}=\frac{40}{78}=\frac{20}{39}
$$
If 2 or 5 turns up after thrown a dice, then select a subject from $A$ otherwise from $B$.
$$
\therefore P(E)=\frac{2}{6} \times \frac{8}{13}+\frac{4}{6} \times \frac{6}{13}=\frac{40}{78}=\frac{20}{39}
$$
Looking for more such questions to practice?
Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.