1 .
Let $X = \{1,2,\dots,100\}$. Let $Y$ be a uniformly random 7-element subset of $X$. Define the event
- A = "the set $Y$ contains at least one even number".
(a)
$\frac{{50 \choose 7}}{{100 \choose 7}}$
(b)
$1 - \frac{{50 \choose 7}}{{100 \choose 7}}$
(c)
$(1/2)^{7}$
(d)
$1 - (1/2)^{7}$