$A$ bag contains $6$ white,$5$ black,and $4$ red balls. Find the probability of getting a white or a black ball when one ball is drawn from the bag.

$A$ card is drawn from a pack of $52$ cards. If $A =$ card is of diamond,$B =$ card is an ace,and $A \cap B =$ card is the ace of diamond,then events $A$ and $B$ are

Let $A$ and $B$ be two events such that $P(A') = 0.3$,$P(B) = 0.4$,and $P(A \cap B') = 0.5$. Then $P(A \cup B')$ is:

One die of red colour,one of white colour and one of blue colour are placed in a bag. One die is selected at random and rolled,its colour and the number on its uppermost face is noted. Describe the sample space.

Three persons work independently on a problem. If the respective probabilities that they will solve it are $\frac{1}{3}$,$\frac{1}{4}$,and $\frac{1}{5}$,then the probability that none of them can solve it is:

In a college,$40 \%$ of students attend the Mathematics class,$30 \%$ of students attend the Physics class,and $20 \%$ of students attend both classes. If a student is chosen at random from the college,what is the probability that the chosen student attends only one class?