If $12$ dice are thrown at a time,then the probability that a multiple of $3$ does not appear on any dice is

The probability of a bomb hitting a bridge is $1/2$ and two direct hits are needed to destroy it. Find the least number of bombs required so that the probability of the bridge being destroyed is greater than $0.9$.

Given that the probability of a man hitting a target with a gun is $\frac{1}{3}$. If he fires $8$ times,then the probability of his hitting the target at least twice is

For an entry to a certain course,a candidate is given $20$ problems to solve. If the probability that the candidate can solve any problem is $\frac{3}{7}$,then the probability that he is unable to solve at most $2$ problems is

If $A$ and $B$ throw two dice $100$ times each simultaneously,then the probability that both of them will get an even number as the total score at the same time in all the throws is

An irregular six-faced die is thrown. The probability that in $5$ throws it will give $3$ even numbers is twice the probability that it will give $2$ even numbers. The number of times,in $6804$ sets of $5$ throws,you expect to get no even number is: