One card is drawn from a well-shuffled deck of $52$ cards. Calculate the probability that the card will
$(i)$ be an ace,
$(ii)$ not be an ace.

In a family having three children,there may be no girl,one girl,two girls,or three girls. So,the probability of each is $\frac{1}{4}$. Is this correct? Justify your answer.

$A$ card is drawn at random from a well-shuffled pack of $52$ cards. Find the probability that the card drawn is a queen.

When a balanced die is rolled,the probability of getting a multiple of $3$ on it is $\ldots \ldots \ldots .$

In a game,the entry fee is $Rs. 5$. The game consists of tossing a coin $3$ times. If one or two heads show,Sweta gets her entry fee back. If she throws $3$ heads,she receives double the entry fee. Otherwise,she will lose. For tossing a coin three times,find the probability that she:
$(i)$ loses the entry fee.
$(ii)$ gets double the entry fee.
$(iii)$ just gets her entry fee back.

The probability of an event $K$ satisfies ...............