If $A$ and $B$ are mutually exclusive events, then the value of $P (A$ or $B$) is
$0$
$-1$
$1$
None of these
A bag contains $9$ discs of which $4$ are red, $3$ are blue and $2$ are yellow. The discs are similar in shape and size. A disc is drawn at random from the bag. Calculate the probability that it will be not blue,
‘$X$’ speaks truth in $60\%$ and ‘$Y$’ in $50\%$ of the cases. The probability that they contradict each other narrating the same incident is
A letter is chosen at random from the word $\mathrm {'ASSASSINATION'}$. Find the probability that letter is a consonant.
Describe the sample space for the indicated experiment: A coin is tossed four times.
Out of $60 \%$ female and $40 \%$ male candidates appearing in an exam, $60\%$ candidates qualify it. The number of females qualifying the exam is twice the number of males qualifying it. A candidate is randomly chosen from the qualified candidates. The probability, that the chosen candidate is a female, is.