$A$ fair coin is tossed repeatedly. If a tail appears on the first four tosses,then the probability of a head appearing on the fifth toss equals:

Let $A$ and $B$ be two finite sets having $m$ and $n$ elements respectively such that $m \le n.$ $A$ mapping is selected at random from the set of all mappings from $A$ to $B$. The probability that the mapping selected is an injection is

$A$ bag contains $6$ red,$4$ white and $8$ blue balls. If three balls are drawn at random,then the probability that $2$ are white and $1$ is red,is

$A$ bag contains $30$ balls numbered from $1$ to $30$. One ball is drawn randomly. The probability that the number on the ball is a multiple of $5$ or $7$ is

The probability that a marksman will hit a target is given as $1/5$. Then his probability of at least one hit in $10$ shots is:

$A$ box contains $6$ black and $4$ red balls. Three balls are drawn at random. What is the probability that one ball is red and the other two are black?