If any four numbers are selected and they are multiplied,then the probability that the last digit of the product will be $1, 3, 5$ or $7$ is

In a simultaneous throw of three coins,what is the probability of getting at least $2$ tails?

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

There are $3$ bags which are known to contain $2$ white and $3$ black balls; $4$ white and $1$ black balls and $3$ white and $7$ black balls respectively. $A$ ball is drawn at random from one of the bags and found to be a black ball. Then the probability that it was drawn from the bag containing the most black balls is

In order to get at least one head with a probability $\ge 0.9$,the minimum number of times a coin needs to be tossed is:

$A$ number is chosen from the first $100$ natural numbers. The probability that the number is even or divisible by $5$ is: