There are 2 shelves. One shelf has 5 Physics and 3 Bilogy books and other has 4 Physics and 2 Biology books.…
There are 2 shelves. One shelf has 5 Physics and 3 Bilogy books and other has 4 Physics and 2 Biology books. Then probability of drawing a Physics book is
$\frac{1}{2}$
$\frac{31}{48}$
$\frac{9}{14}$
$\frac{9}{38}$
Solution
The required probability $=P\left(S_1\right) \cdot P\left(P / S_1\right)+P\left(S_2\right) \cdot P\left(P / S_2\right)$
$=\frac{1}{2} \times \frac{5}{8}+\frac{1}{2} \times \frac{4}{6}=\frac{31}{48}$