The probability of any event cannot be ..........

The probability of the month of February in a non-leap year having $5$ Thursdays is ............

$A$ class consists of $35$ boys and $25$ girls. One student is selected at random to be the class monitor. Find the probability that the selected student is a girl. (in $/12$)

$A$ lot consists of $144$ ball pens of which $20$ are defective and the others are good. Nuri will buy a pen if it is good,but will not buy if it is defective. The shopkeeper draws one pen at random and gives it to her. What is the probability that
$(i)$ She will buy it?
$(ii)$ She will not buy it?

Two balanced dice are rolled simultaneously. Then,the probability that the sum of numbers on the dice is $8$ is ........

The probability of the month of August in any year having $5$ Mondays is ..........