The probability that a leap year selected at random contains either $53$ Sundays or $53 $ Mondays, is
$\frac{2}{7}$
$\frac{4}{7}$
$\frac{3}{7}$
$\frac{1}{7}$
If ${A_1},\,{A_2},...{A_n}$ are any $n$ events, then
Probability that a student will succeed in $IIT$ entrance test is $0.2$ and that he will succeed in Roorkee entrance test is $0.5$. If the probability that he will be successful at both the places is $0.3$, then the probability that he does not succeed at both the places is
Two events $A$ and $B$ will be independent, if
For any two independent events ${E_1}$ and ${E_2},$ $P\,\{ ({E_1} \cup {E_2}) \cap ({\bar E_1} \cap {\bar E_2})\} $ is
Let $A$ and $B$ be two events such that the probability that exactly one of them occurs is $\frac{2}{5}$ and the probability that $A$ or $B$ occurs is $\frac{1}{2}$ then the probability of both of them occur together is