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

Two cards are drawn from a pack of $52$ cards. What is the probability that one of them is a queen and the other is an ace?

The probability that a man will be alive $25$ years hence is $0.3$ and the probability that his wife will be alive $25$ years hence is $0.4$. Find the probability that $25$ years hence,both will be alive.

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

$A$ bag contains $5$ white,$7$ black and $4$ red balls. Three balls are drawn from the bag at random,then the probability that all the three balls are white,is

$A$ card is drawn from a pack of $100$ cards numbered $1$ to $100$. Find the probability of drawing a number which is a square.