What is the probability that a leap year selected at random will contain $53$ Sundays?

$A$ determinant is chosen at random from the set of all determinants of order $2$ with elements $0$ or $1$ only. The probability that the value of the determinant chosen is positive is:

$A$ coin is tossed three times in succession. If $E$ is the event that there are at least two heads and $F$ is the event in which the first throw is a head,then $P\left( \frac{E}{F} \right) = $

In a simultaneous throw of $2$ dice,find $P(A \text{ or } B)$ if $A$ denotes the event 'a total of $11$' and $B$ denotes the event 'an odd number on each die'.

$A$ bag contains tickets numbered from $1$ to $20$. Two tickets are drawn. The probability that both the numbers are prime,is

$A$ bag contains $4$ white,$5$ red,and $6$ blue balls. Three balls are drawn at random. What is the probability that all of them are red?