If the events $A$ and $B$ are mutually exclusive,then $P\left( \frac{A}{B} \right) = $

$3$ coins are tossed. Find the probability of getting at least $1$ head and $1$ tail.

If $A$ and $B$ are mutually exclusive events,then the value of $P(A \text{ or } B)$ is

$1$ bag contains $4$ white and $2$ black balls. Another bag contains $3$ white and $5$ black balls. If $1$ ball is drawn from each bag,find the probability that both balls are black.

An urn contains $25$ balls numbered $1$ to $25$. Suppose an odd number is considered a 'success'. $2$ balls are drawn from the urn with replacement. Find the probability of getting at least one success.

In a single throw of $3$ dice,find the probability of getting a total of $17$ or $18$.