$A$ box contains $10$ good items and $6$ defective items. If one item is selected at random,what is the probability that it is either good or defective?

The chances to fail in Physics are $20 \%$ and the chances to fail in Mathematics are $10 \%$. What are the chances to fail in at least one subject (in $\%$)?

Two persons $A$ and $B$ throw three unbiased dice one after the other. If $A$ gets a sum of $13$,then the probability that $B$ gets a higher sum is:

The probability of hitting a target by three marksmen are $\frac{1}{2}, \frac{1}{3}$ and $\frac{1}{4}$ respectively. The probability that one and only one of them will hit the target when they fire simultaneously,is

The probability of happening of an event $A$ is $0.5$ and that of $B$ is $0.3$. If $A$ and $B$ are mutually exclusive events,then the probability of neither $A$ nor $B$ is

$A$,$B$,$C$ are three horses participating in a race. The probability of horse $A$ to win the race is twice that of horse $B$ and the probability of horse $B$ to win is twice that of horse $C$. Then the probabilities of horses $A$,$B$,and $C$ to win the race are respectively: