For any event $A$,which of the following is true?

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:

If two regular six-sided dice are thrown,the probability that the sum will be a prime number is

There are $n$ letters and $n$ addressed envelopes. The probability that each letter is placed in the correct envelope is:

An urn contains $25$ balls numbered $1$ to $25$. Suppose an odd number is considered a 'success'. $2$ balls are drawn from the urn with replacement. Find the probability of getting exactly one success.

Three dice are thrown. Find the chance of getting a sum of $16$.