$A$ card is drawn at random from a well-shuffled pack of $52$ cards. The probability of getting a two of hearts or a two of diamonds is:

$A$ basket contains $4$ red,$5$ blue,and $3$ green marbles. If three marbles are picked at random,what is the probability that either all are green or all are red?

While dialing a telephone number,an old man forgets the last two digits,remembering only that they are different. If he dials the last two digits at random,what is the probability that the number is dialed correctly?

The corners of regular tetrahedrons are numbered $1, 2, 3, 4$. Three tetrahedrons are tossed. The probability that the sum of the upward corners will be $5$ is

If $A$ and $B$ are two events such that $P(A) = \frac{3}{8}$,$P(B) = \frac{5}{8}$ and $P(A \cup B) = \frac{3}{4}$,then $P(A|B) = $

$A$ committee consists of $9$ experts taken from three institutions $A, B$ and $C$,of which $2$ are from $A, 3$ from $B$ and $4$ from $C$. If three experts resign,then the probability that they belong to different institutions is