MCQ
A bag contains $5$ brown and $4$ white socks. A man pulls out two socks. The probability that these are of the same colour is
  • A
    $\frac{5}{{108}}$
  • B
    $\frac{{18}}{{108}}$
  • C
    $\frac{{30}}{{108}}$
  • $\frac{{48}}{{108}}$

Answer

Correct option: D.
$\frac{{48}}{{108}}$
d
(d) Total socks $ = 5 + 4 = 9$

The number of ways to select $2$ socks out of $9$ = $^9{C_2}$

If number of ways to select both brown socks $ = {\,^5}{C_2}$

And number of ways to select both white socks $ = {\,^4}{C_2}$

$\therefore \,P$ (Both brown or white) $ = \frac{{^5{C_2} + {\,^4}{C_2}}}{{^9{C_2}}} = \frac{{16}}{{36}} = \frac{{48}}{{108}}$.

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