If $P(A \cup B) = 0.8$ and $P(A \cap B) = 0.3,$ then $P(\bar A) + P(\bar B) = $

Three ships $A, B$ and $C$ sail from England to India. If the ratio of their arriving safely are $2 : 5, 3 : 7$ and $6 : 11$ respectively,then the probability of all the ships arriving safely is:

If $A$ and $B$ are mutually exclusive events,$P(A) = \frac{1}{2}$,$P(A \cup B) = \frac{3}{5}$,and $P(B') = p$,then $p = $ . . . . . . .

For two events $A$ and $B$,$P(A)=0.5$,$P(A \cup B)=0.6$ and $P(B)=K$ are given. If $A$ and $B$ are independent events,then $K=$ . . . . . . .

If ${A_1}, {A_2}, ..., {A_n}$ are any $n$ events,then:

The odds against a certain event is $5 : 2$ and the odds in favour of another event is $6 : 5$. If both the events are independent,then the probability that at least one of the events will happen is