A man and his wife appear for an interview for two posts. The probability of the husband's selection is $\frac{1}{7}$ and that of the wife's selection is $\frac{1}{5}$. What is the probability that only one of them will be selected

Three coins are tossed once. Let $A$ denote the event ' three heads show ', $B$ denote the event ' two heads and one tail show ' , $C$ denote the event ' three tails show and $D$ denote the event 'a head shows on the first coin '. Which events are mutually exclusive ?

The probability of drawing a white ball from a bag containing $3$ black balls and $4$ white balls, is

In a single throw of two dice, the probability of obtaining a total of $7$ or $9$, is

Three coins are tossed once. Find the probability of getting at most $2$ heads.