If two balanced dice are tossed once,the probability of the event,that the sum of the integers coming on the upper sides of the two dice is $9$,is

The probability that a contractor will get a plumbing contract is $2/3$ and the probability that he will not get an electric contract is $5/9$. If the probability of getting at least $1$ contract is $4/5$,what is the probability that he will get both?

From a pack of cards,two are drawn,the first being replaced before the second is drawn. Find the probability that the first is a diamond and the second is a king.

The probability of $A, B, C$ solving a problem are $\frac{1}{3}, \frac{2}{7}, \frac{3}{8}$ respectively. If all the three try to solve the problem simultaneously,the probability that exactly one of them will solve it,is

From a pack of $52$ cards,two cards are drawn together at random. What is the probability of both cards being kings?

Suppose $n \ge 3$ persons are sitting in a row. Two of them are selected at random. The probability that they are not together is