The probability of obtaining a sum of $8$ in a single throw of two dice is:

$A$ Chartered Accountant applies for a job in $2$ firms $X$ and $Y$. The probability of his being selected in firm $X$ is $0.7$,and being rejected at $Y$ is $0.5$,and the probability of at least $1$ of his applications being rejected is $0.6$. What is the probability that he will be selected in $1$ of the firms?

$A$ card is drawn from a pack of $52$ cards. Find the probability of getting a spade,an ace,or a red card.

$2$ unbiased dice are thrown. Find the probability that neither a doublet nor a total of $10$ will appear.

$4$ coins are tossed once. Find the probability of getting exactly $3$ tails.

$A$ fair coin is tossed repeatedly. If a tail appears on the first four tosses,then the probability of a head appearing on the fifth toss equals: