1 .
Continuing from the previous question, what is the probability that Nika has not practiced on any of the
actual exam questions?
(a)
$\left. {225 \choose 50} \middle/ {250 \choose 50} \right.$
(b)
$\left. {225 \choose 25} \middle/ {225 \choose 50} \right.$
(c)
$\left. {225 \choose 25} \middle/ {250 \choose 50} \right.$
(d)
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